# Just diagnosed with Carbon - I have questions



## F32Fleet (Jul 14, 2010)

E


glangford said:


> What is the difference between a gas DI engine and diesel, that the gasser can be walnut blasted and the diesel currently not?
> 
> I agree an attachment for walnut blasting would solve everything.


The difference is with regards to the design of the cylinder head. The runners inside the head for the M57 are narrow and curve whereas the gassers don't have this design. The narrow runners make it impossible to reach the valves using current tools. Plus these runners also must be cleaned. This is why BMW has had to send them out for cleaning. It has been costing them a ton of $$ to do it.


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## Hoooper (Jun 17, 2013)

anE934fun said:


> If you are referring to the 5 cylinder mechanical MB 300D diesels, those don't have EGR, so no chance for carbon build-up to occur. Don't know about the emission control systems on the 6.0L trucks, but I would suspect a similar absence of EGR. The 335d engine uses EGR and when carbon is introduced into the intake system, it will attach to surfaces and accumulate over time. Maybe BMW will exhaust through the particulate trap before running it through the EGR in future editions?


I was referring to the more recent ones like an om606 or the om603s. Those both have egr and no buildup issues. Don't know about their more recent blutecs.


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## F32Fleet (Jul 14, 2010)

Hoooper said:


> I was referring to the more recent ones like an om606 or the om603s. Those both have egr and no buildup issues. Don't know about their more recent blutecs.


Answer : have you seen many used ones for sale that were <4 years old with less than 100k miles?


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## Hoooper (Jun 17, 2013)

BMWTurboDzl said:


> Answer : have you seen many used ones for sale that were <4 years old with less than 100k miles?


Well they were built in the 90s so none are in that year range. If you extrapolate that though the answer is yes. There are 200k mile examples with no buildup (200k miles in 15 years, that's just over 50k every 4 years)


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## robster10 (Oct 8, 2012)

Hoooper said:


> Explain how diesel e series Benzes with a turbo 3.0L go for a half million miles without issues. Nearly all of them. They are being worked hard and driven hard by all of their old lady owners? There are plenty of owners of 6.0L and larger trucks who don't drive their trucks hard or tow heavy loads 99% of the time but they aren't dying. Claiming its the fault of a powerful diesel in a less than super heavy heavy car is nonsense


Go on to the truck forums and you'll hear otherwise. If our little 3.0l is doubled to 6.0l than we'd be at 520hp and 892ftlbs relatively speaking for comparison. 2014 trucks have reached +400hp and +800ftlbs. Our cars are older production as well. Many guys have manipulated their egr systems, as well as exhaust to keep things running smooth. Ford, Gm and Dodge! Remember trucks are geared differently than our cars are as well. They do rev higher and are bricks on the road with regards to aerodynamics. More effort to move them down the road. The D's are not even breaking a sweat. Now with regards to the Mercedes. They had there problems with their design as well. But big difference with those 90 models is they had 4 speed where our D's have a 6. Another variable is the 4matic. The driveline puts more load on engine as well driving all 4 wheels. Similar to the x5d.(can't remember any x5 owners chiming in)Our 5th and 6th just dropp the rpms down considerably where in the 4spd the revs climb up higher and longer. Also they made a lot less power in those motors so they have to work harder. So take a look at the new Mercedes and they have similar issues. I've been working across from a Mercedes dealer for a year know and I've gotten to know the techs there and they have problems too! Are all the D's dropping dead here. Not! How you drive, long and hard is a consideration. *fault of a powerful diesel in less than a super heavy car is not nonsense but realistic!*


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## Hoooper (Jun 17, 2013)

A pretty good portion of the ds are affected, more than any of the other models that have been mentioned by a long shot. There is a thread over on e90post about who has it and over 30% of responses are people who have had to have the dealer clean out their buildup because they had engine malfunction/power loss displays. Now, that obviously includes some confirmation bias but even if you figure its 3x the responses that's still 10% of all vehicles, that's nowhere near an acceptable failure rate. The idea that we should blame our build up on gearing, good aerodynamics, or too powerful engine is absurd for an average consumer vehicle. It is a design failure if a vehicle can't survive being driven within the legal limits of its average market and in the manner that 90% of its consumers will drive it. It sure seems like BMW thought they could get away with just running a boatload of egr to meet emissions instead of engineering an actual solution.


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## robster10 (Oct 8, 2012)

Show me an average consumer vehicle making super car torque figures. Guess that's why they discontinued it here. The VWs are successful here in NA but then again they are 4cyl. No where near our cars.


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## Hoooper (Jun 17, 2013)

How are the 335d torque figures somehow an exception to being reliable? Its still very much a normal consumer car, your average buyer for the 335d was not a super car buyer nor were they buying an everyday consumer vehicle expecting it to have worse than supercar reliability


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## crowz (Oct 28, 2006)

robster10 said:


> Show me an average consumer vehicle making super car torque figures. Guess that's why they discontinued it here. The VWs are successful here in NA but then again they are 4cyl. No where near our cars.


Umm actually my 2002 F250 7.3 diesel makes more power than BMW diesels ever dreamed of. Mine isnt "stock" though but I dont have much money invested to get me there.

Injectors plus programmer for the most part = enough power to sling a rod for most diesels.

If there was a market for bmw diesel performance (enough people wanting it) then you would see a huge jump in almost turn key power for the cars. But the people with the most money to spend on diesel performance drive trucks not cars. The average diesel truck in america with a nice factory trim level now cost MORE than a fully luxed bmw diesel.

So the money is in diesel truck performance. Not diesel car performance. Making killer power with a diesel is easy. Its keeping it from grenading from high egt's, boost, and block deformation is the problems. Gas motors are hard to squeeze much out of without heads, boring, etc. Diesels like I said are very easy to get awesome numbers out of as in trippling the power they had leaving the factory on many models. Its making it last when making the power is where the work comes in.


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## Pierre Louis (Oct 23, 2011)

The car diesel market is a lot different than the truck diesel market. It is usually considered to be an untapped market in the US, sort of like smaller diesel light trucks. It hadn't existed until VW resurrected it in the late 1990's. Mercedes was the closest to this, and one cannot imagine a Mercedes driver cross-shopping a super-powered mammoth truck. I'm sure many have looked at trucks, but the fuel economy isn't there as well as any semblance to daily driving outside of a rough rural environment.

Diesel engines have unique characteristics in cars, and they are not bought just for the "power."

PL


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## crowz (Oct 28, 2006)

Pierre Louis said:


> The car diesel market is a lot different than the truck diesel market. It is usually considered to be an untapped market in the US, sort of like smaller diesel light trucks. It hadn't existed until VW resurrected it in the late 1990's. Mercedes was the closest to this, and one cannot imagine a Mercedes driver cross-shopping a super-powered mammoth truck. I'm sure many have looked at trucks, but the fuel economy isn't there as well as any semblance to daily driving outside of a rough rural environment.
> 
> Diesel engines have unique characteristics in cars, and they are not bought just for the "power."
> 
> PL


All the truck owners I know, including myself, buy diesel cars for mpg only. A few mod to get a bit more pep out of them but the cars are what they commute with and use the trucks for playing or towing.

My wifes mercedes 190D turbo was bought for mileage but I was quite suprised how fast that little car is.


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## Pierre Louis (Oct 23, 2011)

crowz said:


> All the truck owners I know, including myself, buy diesel cars for mpg only. A few mod to get a bit more pep out of them but the cars are what they commute with and use the trucks for playing or towing.
> 
> My wifes mercedes 190D turbo was bought for mileage but I was quite suprised how fast that little car is.


Agreed. Which is why the 335d is such a unique animal in the NA market.

PL


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## rg (Dec 24, 2001)

Hoooper said:


> the warranty answer is yes, as long as you are getting fault codes related to carbon. If you just go in and ask to have it cleaned up they will tell you its not warranty.


Back to the warranty question, the BMW extended warranty plans SPECIFICALLY state that carbon build up is NOT covered. I don't have the contract language handy at this moment but I have posted about this previously. I even asked both my dealer and a well respected online seller of the warranties that specific question, and both of them replied that my reading of the contract was correct, BMW does not allow them to cover CBU.

Note that my '11 has ~44K miles and my questions about the warranty have been in the context of trying to decide whether to buy one or not, not actually presenting a car for repair under the warranty. You would think that the dealer(s) would be trying to get me to buy the extended warranty, but basically they're telling me "if you're getting it to protect yourself against the CBU issue, don't".

It would be good to hear categorically from someone who has direct experience with trying to get a car fixed for CBU under the extended warranty...


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## F32Fleet (Jul 14, 2010)

rg said:


> Back to the warranty question, the BMW extended warranty plans SPECIFICALLY state that carbon build up is NOT covered. I don't have the contract language handy at this moment but I have posted about this previously. I even asked both my dealer and a well respected online seller of the warranties that specific question, and both of them replied that my reading of the contract was correct, BMW does not allow them to cover CBU.
> 
> Note that my '11 has ~44K miles and my questions about the warranty have been in the context of trying to decide whether to buy one or not, not actually presenting a car for repair under the warranty. You would think that the dealer(s) would be trying to get me to buy the extended warranty, but basically they're telling me "if you're getting it to protect yourself against the CBU issue, don't".
> 
> It would be good to hear categorically from someone who has direct experience with trying to get a car fixed for CBU under the extended warranty...


While true keep in mind the CBU issue rarely occurs in a vacuum. There usually is a part failure involved. In that case BMW will require CBU cleaned as part of the warranty process. Also it's tremendously cost prohibitive to expect the owner to pay $7,000 out of pocket. It doesn't fit in with their ownership experience. So technically the SA is right but I suspect privately BMW decided to cover it. When it costs less than $800 I bet they stop.

FWIW I am 6 months into the OEM extended warranty and I already broke even over SCR issues


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## anE934fun (May 10, 2008)

BMWTurboDzl said:


> While true keep in mind the CBU issue rarely occurs in a vacuum. There usually is a part failure involved. In that case BMW will require CBU cleaned as part of the warranty process. Also it's tremendously cost prohibitive to expect the owner to pay $7,000 out of pocket. It doesn't fit in with their ownership experience. So technically the SA is right but I suspect privately BMW decided to cover it. When it costs less than $800 I bet they stop.
> 
> FWIW I am 6 months into the OEM extended warranty and I already broke even over SCR issues


Nothing like finding oneself in the thicket of extended warranty coverage. I can speak to how it is handled in CA (personal experience with an aftermarket policy for a non-BMW):

1. CA has a ban of sorts on extended warranty policies that are sold where the warranty company does not have a presence in CA. This means the policies are primarily sold through dealers. While this may seem to be an add-on to the cost of the policy, it has its advantages when it comes time to collect on the policy....

2. If you have an excluded items (everything is covered unless it is on a list of not covered (excluded) items) policy, with a documented failure (item doesn't meet manufacturer spec) and there is no abuse/owner non-standard mods, the policy must cover the repair. If the warranty company refuses to cover the repair, the CA Dept. of Insurance can put their CA business in jeopardy.

So, back to the present - if all failures due to carbon build-up are excluded, you are basically screwed. But there may be an intermediate outcome - if the SES LED lights up and codes are thrown with the car going into limp mode, and one of the repair items involves a cleaning of the intake and head, with other covered items being replaced, you are probably in a good position to get most of the repair expense covered (all items that are not directly related to the carbon cleaning). Best of all outcomes though, is where there is no exclusion for carbon build-up.

With the above in mind, I read every paragraph of the extended warranty policy I purchased for my d to be certain there was no exclusion for carbon build-up, and there isn't. I purchased peace-of-mind, and if I get hit with carbon build-up that causes SES to light up, and codes to be thrown, I should have the policy cost paid back and then some.


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## robster10 (Oct 8, 2012)

crowz said:


> All the truck owners I know, including myself, buy diesel cars for mpg only. A few mod to get a bit more pep out of them but the cars are what they commute with and use the trucks for playing or towing.
> 
> My wifes mercedes 190D turbo was bought for mileage but I was quite suprised how fast that little car is.


A few mods but do they come close to a stock 335d? If there is a problem than why don't we all have it. It seems that guys having problems with carbon issues are the ones with low mileage (daily usage). These cars probably don't even get warmed up before they are parked again. This is why some of us are saying to play hard with the car to clean out the crud. I don't mean constantly WOT breaking the speed limits. I drive at least 80 miles one way for my commute. 50-60mph average. What kind of mileage do you do a year? 10-20-30k or more K a year. The guys I know with diesel cars like myself drive 3-4 times more than average drivers. This is where the diesel makes up the mpg over a gasser. So if the carbon has built up after only 30-40k how much was the car driven?


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## DaveN007 (Oct 4, 2013)

robster10 said:


> A few mods but do they come close to a stock 335d? If there is a problem than why don't we all have it. It seems that guys having problems with carbon issues are the ones with low mileage (daily usage). These cars probably don't even get warmed up before they are parked again. This is why some of us are saying to play hard with the car to clean out the crud. I don't mean constantly WOT breaking the speed limits. I drive at least 80 miles one way for my commute. 50-60mph average. What kind of mileage do you do a year? 10-20-30k or more K a year. The guys I know with diesel cars like myself drive 3-4 times more than average drivers. This is where the diesel makes up the mpg over a gasser. So if the carbon has built up after only 30-40k how much was the car driven?


Blaming carbon build up on normal driving is like blaming rape on "not wearing a Burkha".

Show me in the BMW literature where it says:

"Warning: If you drive less than 20,000 miles a year, your car will become choked with soot and die"

or

"We know we told you that this car gets great fuel economy, but if you drive it in a way that actually achieves that economy you might as well shoot bacon grease into your carotid artery every day."

We hope (not a strategy) that because we drive like hooligans that we will be spared carbon build up because a rolling stone gathers no moss. I love the rationalization, but let's not get too delusional here.


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## Diesel Power (Oct 2, 2010)

robster10 said:


> A few mods but do they come close to a stock 335d? If there is a problem than why don't we all have it. It seems that guys having problems with carbon issues are the ones with low mileage (daily usage). These cars probably don't even get warmed up before they are parked again. This is why some of us are saying to play hard with the car to clean out the crud. I don't mean constantly WOT breaking the speed limits. I drive at least 80 miles one way for my commute. 50-60mph average. What kind of mileage do you do a year? 10-20-30k or more K a year. The guys I know with diesel cars like myself drive 3-4 times more than average drivers. This is where the diesel makes up the mpg over a gasser. So if the carbon has built up after only 30-40k how much was the car driven?


If my issue is attributable to carbon buildup, then that won't support the infrequent/low mileage premise. My daily commute is 75 miles RT with 60 of those miles traveling at an average speed of 75 MPH. I just passed the 65K mark today.


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## rg (Dec 24, 2001)

anE934fun said:


> With the above in mind, I read every paragraph of the extended warranty policy I purchased for my d to be certain there was no exclusion for carbon build-up, and there isn't.


Which [warranty] company is this? Maybe that's what I should get!


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## robster10 (Oct 8, 2012)

Diesel Power said:


> If my issue is attributable to carbon buildup, then that won't support the infrequent/low mileage premise. My daily commute is 75 miles RT with 60 of those miles traveling at an average speed of 75 MPH. I just passed the 65K mark today.


75 miles RT. What year is your D? I do 80miles/130km one way. This is why I bought the D. Even the dealer here told me that if you don't drive 40K km/24K miles a year than the diesel isn't for you.


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## robster10 (Oct 8, 2012)

DaveN007 said:


> Blaming carbon build up on normal driving is like blaming rape on "not wearing a Burkha".
> 
> Show me in the BMW literature where it says:
> 
> ...


Research about diesels. Strengths and weakness. They are not short commute cars. Show me in any auto literature that tells you how to drive the car, normal driving???? Really! Experience from experienced diesel owners and mechanics gives you more insight. Look up what journalist would recommend as the rational to buy a diesel car. With your logic everyone can go out and by a ford Eco boost f-150 +30 mpg. Forgot to tell you it gets this on a flat road, with no load, no passengers and no headwind. :rofl:


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## crowz (Oct 28, 2006)

robster10 said:


> A few mods but do they come close to a stock 335d? If there is a problem than why don't we all have it. It seems that guys having problems with carbon issues are the ones with low mileage (daily usage). These cars probably don't even get warmed up before they are parked again. This is why some of us are saying to play hard with the car to clean out the crud. I don't mean constantly WOT breaking the speed limits. I drive at least 80 miles one way for my commute. 50-60mph average. What kind of mileage do you do a year? 10-20-30k or more K a year. The guys I know with diesel cars like myself drive 3-4 times more than average drivers. This is where the diesel makes up the mpg over a gasser. So if the carbon has built up after only 30-40k how much was the car driven?


Actually from what I read I think I know why the short distance driving people have the problem more than the long distance ones. Regen mode. Raising the temps super hot to regenerate while not getting up to speed (higher rpms) for any length of time causes it to cake up faster.

I dont believe this will keep the ones driving further at once like yourself from eventually having the problem but I do imagine its delaying when it happens.

Egr + diesel motor = bad. But its what manufacturers have to do to meet rather stupid emmision laws. Im not one of those anti emission control types. But why is it fair to make a diesel have lower emissions than a gas motor? By nature diesels are clearner then gas motors emissions wise. The smoke they put out is mostly harmless and the regulations put in place were not to "save" the enviroment as much as people couldnt stand the sight of diesels smoking.

The higher emissions of NOx and particles aka soot that diesels put out has a short term but higher enviromental effect than the longer lasting but greater effecting emissions of the gas motors. So basically if the soot stays in the air it can cause faster global warming but thats the kicker, soot settles pretty fast. The dpf collector crap requiring regen has caused more obvious problems than its helped. Like fires. Fires are bad. Especially when you burn down your garage/house or catch trees in the yard on fire and or burn other cars around you. Google that some, its been a problem with dpf and regen modes. It can cause some nice flamethrower effects in the right conditions.

All my babbling is getting at the fact they need to go back to the drawing board on the diesel motors for emission stuff.

Egr + diesel = bad, dpf isnt very healthy either at times


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## crowz (Oct 28, 2006)

DaveN007 said:


> Blaming carbon build up on normal driving is like blaming rape on "not wearing a Burkha".
> 
> Show me in the BMW literature where it says:
> 
> ...


Well actually blaming carbon buildup on how you drive is precisely how to determine how to get around the problem somewhat.

That said that doesnt let bmw off the hook or any of the other manufacturers. Im not saying that means you are getting what you deserve. Im just saying that might be WHY a certain amount of the drivers have the problem more than others and at a lower mileage point.

Still shouldnt let bmw off the hook for repairs of it under warranty. After warranty if I had one Id nuke the egr and dpf


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## Pierre Louis (Oct 23, 2011)

I've typed this a few times, but this might be a good thread to post it again on. I'm on my 5th diesel, the first was a 7.3 Navistar powered motorhome. The last three didn't have DPF's, so when I mashed the throttle actually causing a strong downshift, a nice plume of black smoke would come out the exhaust. This may have "cleaned out" the carbon buildup, since the cars I've had were way past 150,000 miles and had no carbon issues when they were sold. BTW, all except the Navistar had EGR.

So because of the massive power in my 335d and my penchant for fuel economy, I stopped doing this "downshift power maneuver" until I got worried about carbon buildup and tried it. Well, that probably cooked my catalytic converters, since it had a larger than usual load of crud coming through and they apparently couldn't handle it. A little research revealed that if the catalytic converters are overloaded, the resulting "burn" can damage them.

I admit the above is not very evidence based and is anecdotal, but it makes a bit of sense to me anyway. I have since been doing the power downshift in the 335d and it seems to like it. The DPF seems to be doing its job too.

PL


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## Hoooper (Jun 17, 2013)

Long drives don't stop the buildup. I drive well over 20k per year, 70mi round trip commute with 68 of that being highway, and when I visually checked for buildup in the intake and heads there was a layer well over 1mm thick. My intake did not look very different than the intakes we've seen from people who's cars have been dealer treated for CBU. That's when I blocked the egr and started running meth. Long commutes can help prolong it, and lots of short trips can exacerbate it, but both will land you in the dealership sooner or later unless you are lucky.


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## F32Fleet (Jul 14, 2010)

hoooper said:


> long drives don't stop the buildup. I drive well over 20k per year, 70mi round trip commute with 68 of that being highway, and when i visually checked for buildup in the intake and heads there was a layer well over 1mm thick. My intake did not look very different than the intakes we've seen from people who's cars have been dealer treated for cbu. That's when i blocked the egr and started running meth. Long commutes can help prolong it, and lots of short trips can exacerbate it, but both will land you in the dealership sooner or later unless you are lucky.


1


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## Hoooper (Jun 17, 2013)

FWIW, here is a comparison of mine, one that was getting limp modes from build up, and an extreme case.

Edit: for clarity, I never had codes, driveability issues, poor MPG, or other symptoms of CBU
Mine









One with limp mode, very similar to mine









The extreme example


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## F32Fleet (Jul 14, 2010)

Great examples. That last one had some serious issues. TBH I wouldn't mind cleaning mine off. Spray some of my Lubro-Moly Intake Cleaner


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## Flyingman (Sep 13, 2009)

I don't see how one wouldn't detect such high levels of CBU. Has to be detrimental to performance one way of the other, power and/or MPG. I'm looking closely for the signs. Perhaps more frequent Regens, drop in MPG, increase in engine loading for similar speeds.

I agree it is most likely just a matter of time before it hits. EGR removal is a duty then!:thumbup:


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## montr (Oct 7, 2006)

Hoooper, The BMW instructions for removal and re-installing the intake manifold say to replace all seals (6 round + 6 square seal) with new one. Did you re-use yours?
Thanks


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## quasimodem (Nov 9, 2011)

BMWTurboDzl said:


> While true keep in mind the CBU issue rarely occurs in a vacuum.


Not true, the intake manifold is a common place for CBU.:eeps:


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## F32Fleet (Jul 14, 2010)

quasimodem said:


> Not true, the intake manifold is a common place for CBU.:eeps:


. you're misreading what I said. I was speaking on terms of a warranty claim. Rarely will it happen by itself (i.e in a vacuum).. Built up inside the intake doesn't always necessitate a warranty claim by itself.


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## Hoooper (Jun 17, 2013)

montr said:


> Hoooper, The BMW instructions for removal and re-installing the intake manifold say to replace all seals (6 round + 6 square seal) with new one. Did you re-use yours?
> Thanks


Yes I reused mine. No issues



quasimodem said:


> Not true, the intake manifold is a common place for CBU.:eeps:


Aside from the fact that the intake is under pressure basically at all times except idle, diesel intakes aren't really in vacuum anyway due to no throttle. Might be able to measure a tiny amount at idle, but there's a good reason why we have a vacuum pump


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## quasimodem (Nov 9, 2011)

Hoooper said:


> Aside from the fact that the intake is under pressure basically at all times except idle, diesel intakes aren't really in vacuum anyway due to no throttle. Might be able to measure a tiny amount at idle, but there's a good reason why we have a vacuum pump


Damn, my mistake. Shows you how much I know about diesel engines. :bawling:


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## montr (Oct 7, 2006)

Hoooper, Did you clean the intake manifold? If yes, how?
I plan to remove mine to clean it when I have some time available.
Thanks


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## quasimodem (Nov 9, 2011)

crowz said:


> The higher emissions of NOx and particles aka soot that diesels put out has a short term but higher enviromental effect than the longer lasting but greater effecting emissions of the gas motors. So basically if the soot stays in the air it can cause faster global warming but thats the kicker, soot settles pretty fast. The dpf collector crap requiring regen has caused more obvious problems than its helped. Like fires. Fires are bad. Especially when you burn down your garage/house or catch trees in the yard on fire and or burn other cars around you. Google that some, its been a problem with dpf and regen modes. It can cause some nice flamethrower effects in the right conditions.


If only our cars actually emitted flames out of the tailpipes under regen.:flame:


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## anE934fun (May 10, 2008)

rg said:


> Which [warranty] company is this? Maybe that's what I should get!


Allstate. The downside for you is that you don't have the State of TX as your advocate like CA does for its residents. The warranty that the CA Dept. of Insurance got involved with on my behalf was written by EasyCare. Originally, EasyCare denied $2,800 in extended warranty repairs to suspension components on a Volvo that I own. There was clear proof the suspension components had failed (the car could not be aligned to spec, photographic proof that the parts had failed, and, and, and). I sent a letter to the CA Dept. of Insurance with copies of the repair invoice that stated EasyCare's denial of coverage and the pics of the failed parts plus the alignment fail print-out. About 20 days later, I get a copy of a letter from the CA Dept. of Insurance to EasyCare asking for their reasons for denial of coverage. Five days after receiving the copy of the letter from CA Dept. of Insurance, I get contacted by EasyCare asking where to send a check.

The problem with extended warranty coverage is that the insurance company has the power position - if they deny coverage, you have limited recourse to compel them to pay the claim. CA has set up the Dept. of Insurance with the ability to shut down the revenue flow from policies sold in CA, so there is a huge motivator for insurance companies to not f*ck with CA policy holders.


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## Hoooper (Jun 17, 2013)

quasimodem said:


> Damn, my mistake. Shows you how much I know about diesel engines. :bawling:


Yeah, I'm doing a lot of learning also. My first diesel



montr said:


> Hoooper, Did you clean the intake manifold? If yes, how?
> I plan to remove mine to clean it when I have some time available.
> Thanks


I tried to clean it but didn't have much success. I used engine degreaser, brake cleaner, carb cleaner, dish soap. Blasting water in with a hose nozzle got the most out.


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## anE934fun (May 10, 2008)

Hoooper said:


> Snip...
> 
> *I tried to clean it but didn't have much success*. I used engine degreaser, brake cleaner, carb cleaner, dish soap. Blasting water in with a hose nozzle got the most out.


B100 would have made short work of the baked on crud. Might have had to let it sit overnight, but B100 is one of the best solvents around.


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## crowz (Oct 28, 2006)

anE934fun said:


> B100 would have made short work of the baked on crud. Might have had to let it sit overnight, but B100 is one of the best solvents around.


Just remember if you havent run b100 before a fuel filter change is usually a good idea after the tank or two of it.

It will clean EVERYTHING out of the tank and lines and deposit in your filter.


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## anE934fun (May 10, 2008)

crowz said:


> Just remember if you havent run b100 before a fuel filter change is usually a good idea after the tank or two of it.


I am not referring to running B100 as a fuel. Use B100 as a dip - dunk the clogged intake in a tank of B100 overnight.



> It will clean EVERYTHING out of the tank and lines and deposit in your filter.


Including the carbon in the head or intake. :thumbup:


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## F32Fleet (Jul 14, 2010)

anE934fun said:


> I am not referring to running B100 as a fuel. Use B100 as a dip - dunk the clogged intake in a tank of B100 overnight.
> 
> Including the carbon in the head or intake. :thumbup:


Diesel fuel in general will do the same. Wouldn't have to necessarily be bio.


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## anE934fun (May 10, 2008)

BMWTurboDzl said:


> Diesel fuel in general will do the same. Wouldn't have to necessarily be bio.


I spilled a tiny amount (<1/4 teaspoon) of B100 on a painted shelf about a year ago, and within 2 or 3 days later, about a 1" diameter spot of the paint had lifted where the B100 was spilled. I have used D2 as a parts degreaser (D2 is basically kerosene) for ever with no lifting of painted surface where drops would occur when splashing during cleaning.

Diesel is a good cleaning agent, but B100 is better.


----------



## robster10 (Oct 8, 2012)

Found this topic on *you tube*but couldn't insert. Amsoil rep talks about the problems associated with the DPF , EGR etc.on diesels. Maybe someone here can attach this link please. "*Understanding Diesel DPF Regeneration"* importance of minimizing the regen cycles.


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## Mbrown328dx (Mar 22, 2014)

I had a 2009 Dodge Challenger SRT8 and they had a serious problem with the intake building up with soot/sludge/carbon buildup(was labeled different names depending on who you talked to) and the main cause of the problem was the excessive oil vapor that came from the erg to the intake. It was causing car to run poorly and lose power and performance. The problem was solved by adding an aftermarket oil catch can. I did this and was amazed how much oil accumulated in it in just a months time. Would this maybe be a fix or at least a method to slow down the carbon build up. I will be getting my first BMW in May which is. 328d x and if I can prevent or slow down this problem I want to do it. Any ideas?


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## robster10 (Oct 8, 2012)

The other part of the equation is the DPF building up with soot. Then regen cycle cleans the DPF but taints the oil. Then the egr sends the gaseous vapours into the intake which mixes with the oil that is being drawn up into the intake. Then over time the build up occurs in the intake tract, but sooner for some than others. From what I understand it's better to go through less regen cycles via pushing the motor more often cleaning the DPF with hotter exaust temps that won't happen with "normal puttering around driving". Diesels run cooler than a gasser so more problems happening here with our systems. The oil catch can is some help but the EGR and DPF combo is the problem here.


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## anE934fun (May 10, 2008)

Mbrown328dx said:


> I had a 2009 Dodge Challenger SRT8 and they had a serious problem with the intake building up with soot/sludge/carbon buildup(was labeled different names depending on who you talked to) and the main cause of the problem was the excessive oil vapor that came from the erg to the intake. It was causing car to run poorly and lose power and performance. The problem was solved by adding an aftermarket oil catch can. I did this and was amazed how much oil accumulated in it in just a months time. Would this maybe be a fix or at least a method to slow down the carbon build up. I will be getting my first BMW in May which is. 328d x and if I can prevent or slow down this problem I want to do it. Any ideas?


If you were taking delivery of a gasser, I would say that an oil vapor catch can wouldn't hurt, as crankcase vapor is supposed to be a large part of the root cause of the carbon build-up (CBU) on the gassers. However, on the d, the root cause of CBU is the EGR function. A catch can has no impact on EGR.

Edit: After reading Hooper's post at #89 below, there may be some benefit from installing a catch can to filter out the crankcase vapors. Earlier pics that were posted of the intake by Hooper at post #67 gave me the impression that EGR was the root cause of the coking (dry, baked-on appearance of the CBU). But it could be a combination of crankcase vapors blending with exhaust particulates to form the coke-like deposits that are clogging the intake in Hooper's extreme example pic. I am curious whether the methanol injection alone would make a meaningful difference in the coking. Hooper, any interest in being the guinea pig for the rest of us (as in put the EGR back in working condition but leave the methanol injection functioning)? One bit of information begets more questions....


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## anE934fun (May 10, 2008)

robster10 said:


> The other part of the equation is the DPF building up with soot. Then regen cycle cleans the DPF but taints the oil. Then the egr sends the gaseous vapours into the intake which mixes with the oil that is being drawn up into the intake. Then over time the build up occurs in the intake tract, but sooner for some than others. From what I understand it's better to go through less regen cycles via pushing the motor more often cleaning the DPF with hotter exaust temps that won't happen with "normal puttering around driving". Diesels run cooler than a gasser so more problems happening here with our systems. The oil catch can is some help but *the EGR and DPF combo is the problem here*.


I believe the DPF does its thing post EGR. If particulate filtering was done before EGR, there would be considerably less CBU.


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## Hoooper (Jun 17, 2013)

for what it is worth in this thread, here is a post from me on e90post about the carbon build up/egr

www.e90post.com/forums/showthread.php?t=961958


Hoooper said:


> I blocked my EGR in December and have been running water/meth since around August. The pictures speak for themselves.
> 
> Before
> 
> ...


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## F32Fleet (Jul 14, 2010)

anE934fun said:


> I believe the DPF does its thing post EGR. If particulate filtering was done before EGR, there would be considerably less CBU.


I also think people don't understand that we have EGR to reduce combustion temps for emissions (reduced temps lower NOx).

It would be interesting to see how well the UREA system responds to the increased levels of NOX


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## F32Fleet (Jul 14, 2010)

Hoooper said:


> for what it is worth in this thread, here is a post from me on e90post about the carbon build up/egr
> 
> www.e90post.com/forums/showthread.php?t=961958


Photos of the valves would tell us whether this rigged addition is worth it.


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## Hoooper (Jun 17, 2013)

BMWTurboDzl said:


> I also think people don't understand that we have EGR to reduce combustion temps for emissions (reduced temps lower NOx).
> 
> It would be interesting to see how well the UREA system responds to the increased levels of NOX


I dont think it made much difference, I filled up UREA around 62-65k miles, and then my next fill was just a week ago at 78k. I was actually starting to wonder if the EGR delete had for whatever reason disabled UREA injection since it seemed like it had been forever



BMWTurboDzl said:


> Photos of the valves would tell us whether this rigged addition is worth it.


You dont think that the difference in the gunked up wall just a couple centimeters before the valves is representative of the situation? The valves may not be quite as clean but to believe they arent improving would be lying to yourself. Without the EGR soot they are going to get better. If they then become susceptible to gasser type valve buildup thats still a pretty good trade seeing as they often go 80k plus without a cleaning and they arent really having limp modes and several thousand $$$ bills to fix it.


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## anE934fun (May 10, 2008)

BMWTurboDzl said:


> I also think people don't understand that we have EGR to reduce combustion temps for emissions (reduced temps lower NOx).
> 
> *It would be interesting to see how well the UREA system responds to the increased levels of NOX*


Probably see increased consumption of DEF in response to higher output of NOx. Unless the DEF injection is not based on actual sensed NOx emissions, but is just driven by exhaust gas flow, without testing/sampling for NOx presence in the exhaust.

Edit: Based on Hooper's response above, it seems like there is no sampling, just spraying in response to flow.


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## anE934fun (May 10, 2008)

Hoooper said:


> for what it is worth in this thread, here is a post from me on e90post about the carbon build up/egr


Hooper, how did you configure your water/meth injection? To spray into the air intake? Or? Are you using the water/meth injection to cool & wash the intake path? Or are you doing something else with the injection (some gassers are using methanol injection as an alternative to Nitrous injection)?


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## Hoooper (Jun 17, 2013)

anE934fun said:


> Hooper, how did you configure your water/meth injection? To spray into the air intake? Or? Are you using the water/meth injection to cool & wash the intake path? Or are you doing something else with the injection (some gassers are using methanol injection as an alternative to Nitrous injection)?


Its set up with the nozzle in the charge air pipe about a foot before the EGR valve. It sprays progressively, starting at a low rate at 10PSI boost or around there and increasing rate as boost builds. The controller is set up by BMS so I dont know exactly what the parameters are.


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## quasimodem (Nov 9, 2011)

anE934fun said:


> Hooper, how did you configure your water/meth injection? To spray into the air intake? Or? Are you using the water/meth injection to cool & wash the intake path? Or are you doing something else with the injection (some gassers are using methanol injection as an alternative to Nitrous injection)?


Hmm, your sig reminds me that I saw a black on black 335d today on Haight street. If your interior is beige or brown, like in your signature, I guess it wasnt you.


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## anE934fun (May 10, 2008)

quasimodem said:


> Hmm, your sig reminds me that I saw a black on black 335d today on Haight street. *If your interior is beige or brown, like in your signature, I guess it wasnt you*.


No, it wasn't me. I have been in S.F. with my d, but not today. I prefer long drives to Napa/Sonoma to plodding from stop light to stop light with my d.


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## wkahn1961 (Apr 13, 2010)

I did get my car back after two weeks and a day with the dealer. They said it would have been closer to a $5000 repair. They had estimated $7000 initially.

They told me that the EGR valve is an updated version from what the car had when it was built, so its possible there may be some improvement in this issue. But they gave me no guarantees. 

24 hours after getting the car, the yellow light came on again. Today they tell me its a fuel injector needing to be recalibrated. 

They claim they saw this same issue in another diesel that they cleaned. 

The car now runs better - seems like it has more power and the fuel mpg is better all of a sudden for in town driving.


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## Hoooper (Jun 17, 2013)

The EGR was updated a while ago. It was a fix for the actual egr but it doesn't seem to mean anything for the buildup.


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## Diesel Power (Oct 2, 2010)

Diesel Power said:


> I'm experiencing similar issues with my 2011 335d. The engine malfunction warning message triggers mostly during below freezing temps sometimes in conjunction with the SES light. It been serviced twice during the past 30 days for the same issue. The air intake hose was replaced the first time due to leaks (BMWNA goodwill) and on Tuesday the air meter assembly was replaced. This morning, the engine malfunction message triggered again during the morning commute.
> 
> My car has about 65K and a trusted "Indy" believes the root cause of the problem is carbon build up. Fortunately, I have an extended warranty.
> 
> ...


Good news today. BMW is going to take care of my 335d. Cleaning of intake and valves is being outsourced. I'll post a follow-up after I get my car back.


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## Hangman4358 (Nov 26, 2013)

Glad to hear BMW got its act together and has recognized the problem and is remedying it for all you 335d owners.


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## quasimodem (Nov 9, 2011)

Flyingman said:


> And the truth shall set you free!!!:freakdanc
> 
> OK, boys, hot off the press as of April. SIB from BMW on how they can clean the carbon out of your 335Ds! It appears to be a rather complex operation involving wands of various sizes and lengths, walnut shells, solvents, etc....
> 
> ...


Blah, how much harder is it to remove the head and do it right? I assume all headbolts have to be replaced , but nothing wrong with a new headgasket....


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## Flyingman (Sep 13, 2009)

quasimodem said:


> Blah, how much harder is it to remove the head and do it right? I assume all headbolts have to be replaced , but nothing wrong with a new headgasket....


I tend to agree that removing the head for cleaning would appear to be "neater", but then it also boils down to cost which is manhours. BMW didn't dream this SIB up without lot's of internal debate and discussion, and you really do want to believe they know what they are doing. But then they got us into this mess in the first place, no?

I do plan to reach out to my local Indy BMW shop and see what his opinion is about all of this. He was the one that had offered to try using a liquid bath method, in situ. I don't like the idea of having to do each cylinder one by one at TDC to avoid possible debris entering the cylinder.

However the walnut shell blasting is apparently effective for some typical applications. I'd have to get a good understanding of just how much carbon and it's consistency to know if it is reasonable to remove with liquids, shells or removing the intake manifold and head all together.

But at least we now have something in writing to throw back at the SA when they give you a load of psycho-babble.


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## quasimodem (Nov 9, 2011)

And is there an expected lifetime for the headgasket anyway? If the CBU doesnt start too fast, and the car can reach the date the headgasket should be replaced, just do it all then.


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## F32Fleet (Jul 14, 2010)

Flyingman said:


> And the truth shall set you free!!!:freakdanc
> 
> OK, boys, hot off the press as of April. SIB from BMW on how they can clean the carbon out of your 335Ds! It appears to be a rather complex operation involving wands of various sizes and lengths, walnut shells, solvents, etc....
> 
> ...


Looks a little more involved when compared to the N55/N45 since our cylinder heads are different. Any word on the cost?


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## F32Fleet (Jul 14, 2010)

quasimodem said:


> Blah, how much harder is it to remove the head and do it right? I assume all headbolts have to be replaced , but nothing wrong with a new headgasket....


Don't forget they also have to remove the valve train, add new coolant and oil. Walnut blasting is always preferable to opening up an engine.


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## Diesel Power (Oct 2, 2010)

Correct on the coolant and oil replacement.


Sent from BimmerApp mobile app


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## anE934fun (May 10, 2008)

Flyingman said:


> I tend to agree that removing the head for cleaning would appear to be "neater", but then it also boils down to cost which is manhours. BMW didn't dream this SIB up without lot's of internal debate and discussion, and you really do want to believe they know what they are doing. But then they got us into this mess in the first place, no?
> 
> I do plan to reach out to my local Indy BMW shop and see what his opinion is about all of this. He was the one that had offered to try using a liquid bath method, in situ. *I don't like the idea of having to do each cylinder one by one at TDC to avoid possible debris entering the cylinder*.
> 
> ...


How else do you blast off the CBU without removing the head? Putting a solvent in the intake path with open valves would require the engine oil to be replaced along with the de-carbonization work.

Sounds like six of one vs. half dozen of another.


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## Flyingman (Sep 13, 2009)

anE934fun said:


> How else do you blast off the CBU without removing the head? Putting a solvent in the intake path with open valves would require the engine oil to be replaced along with the de-carbonization work.
> 
> Sounds like six of one vs. half dozen of another.


They can only do one cylinder at a time, with valves closed so the liquid (if wet clean) or walnut shells (dry clean) don't enter the combustion chamber.

Tedious, time consuming, p in the a, but doable. Haven't you seen the video of the walnut blasting of a BMW engine? Blow and suck, blow and suck,:rofl::rofl: or is it suck and blow?:rofl:

Anyway, if they have developed a SIB, they should be able to do it.

I'm guessing they will charge upwards of $2k to do this though. Still a pretty penny.

I'll see what my Indy guy can do it for. I'll ask him to quote removing head and doing it in situ as per this SIB.


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## quasimodem (Nov 9, 2011)

Flyingman said:


> They can only do one cylinder at a time, with valves closed so the liquid (if wet clean) or walnut shells (dry clean) don't enter the combustion chamber.
> 
> Tedious, time consuming, p in the a, but doable. Haven't you seen the video of the walnut blasting of a BMW engine? Blow and suck, blow and suck,:rofl::rofl: or is it suck and blow?:rofl:
> 
> ...


The scary part for me is trusting someone to have some properly dulled picks scraping CBU from aluminum "by feel". When he gets through the CBU he should stop the scraping because he can "feel" the difference.

I might trust a blind mechanic here. :eeps:


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## mattebury (Feb 2, 2014)

https://www.youtube.com/watch?feature=player_detailpage&v=6n-F73rQZDo

Here's a video


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## Flyingman (Sep 13, 2009)

mattebury said:


> https://www.youtube.com/watch?feature=player_detailpage&v=6n-F73rQZDo
> 
> Here's a video


Pretty much what the new SIB is talking about although I understand the 335D Intake is more complicated, thus several different wands are required. At the end he says he charges 1/2 what the dealer charges, around $550-$650, so double that at least for the dealer charge, $1,200 - $1,500 perhaps, but again, the 335D is more complex and I'd say more manhours than the 335i shown in this video. Thus a $2,000 figure in my estimation.

So there you have it, in a "nutshell"!:thumbup:


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## F32Fleet (Jul 14, 2010)

quasimodem said:


> The scary part for me is trusting someone to have some properly dulled picks scraping CBU from aluminum "by feel". When he gets through the CBU he should stop the scraping because he can "feel" the difference.
> 
> I might trust a blind mechanic here. :eeps:


Meh...these guys have been doing it on the N54 since 2008 or so. Walnut blasting is not new to them.


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## KeithS (Dec 30, 2001)

I noticed in the PDF that the procedure is listed as 32 FRU (Flat Rate Units). An FRU in BMW speak is 1/10 of an hour or 6 minutes. Doesn't seem long enough to do everything but may be the walnut shell blasting part of the procedure. The time to pull things apart (intake and valve cover) and reassemble is probably already documented with FRUs somewhere else.


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## quasimodem (Nov 9, 2011)

mattebury said:


> https://www.youtube.com/watch?feature=player_detailpage&v=6n-F73rQZDo
> 
> Here's a video


Nice video, thanks. Doesnt look as bad as I thought. It also looks like they do have visual access when scraping with the picks.


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## Flyingman (Sep 13, 2009)

quasimodem said:


> Nice video, thanks. Doesnt look as bad as I thought. It also looks like they do have visual access when scraping with the picks.


Caution, that is a 335i, not a 335D. The intake manifold is much more complex on the D with the swirl plates, etc...

But I agree, definitely looks like a viable solution to the CBU problem.


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## zach0726 (Oct 23, 2011)

Flyingman said:


> And the truth shall set you free!!!:freakdanc
> 
> OK, boys, hot off the press as of April. SIB from BMW on how they can clean the carbon out of your 335Ds! It appears to be a rather complex operation involving wands of various sizes and lengths, walnut shells, solvents, etc....
> 
> ...


This is huge news, isn't it? Although I haven't (yet) had an issue with carbon build-up this had been my only issue with the 335d

(64k miles, 80mi/day highway commute, 80% Shell Diesel, 20% Chevron)


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## GreekboyD (Jan 25, 2012)

zach0726 said:


> This is huge news, isn't it? Although I haven't (yet) had an issue with carbon build-up this had been my only issue with the 335d
> 
> (64k miles, 80mi/day highway commute, 80% Shell Diesel, 20% Chevron)


Sadly, it's not a matter of if but when.


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## zach0726 (Oct 23, 2011)

GreekboyD said:


> Sadly, it's not a matter of if but when.


True enough - but I am relieved to see a $1-2k solution that's sanctioned by BMW. Its the $10-15k "custom job" that had me concerned


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## GreekboyD (Jan 25, 2012)

zach0726 said:


> True enough - but I am relieved to see a $1-2k solution that's sanctioned by BMW. Its the $10-15k "custom job" that had me concerned


True.


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## Hoooper (Jun 17, 2013)

82k and no carbon issues. EGR delete helps that though :flush:


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## kimbersc (Mar 6, 2013)

DieselRacer said:


> best news I have heard today, im getting ready to buy one with 49500 miles and has the extended warranty till 100,000, I scared to pull the trigger after doing about a week of reading on the subject...


I bought mine CPO at 48k and had the warranty as well. Had carbon buildup but all covered under warranty with SES. Nothing to worry about.



quasimodem said:


> Not turning over makes no sense. Maybe that is an incorrect description of the problem. The starter motor alone should be able to turn over the engine. I guess if there is some computer problem and the starter motor isnt being told to "engage" then it could be an electrical/computer problem otherwise it would be just a simple starter motor problem.
> 
> Come to think of it, something in the engine might not be working and, based on that failure, the computer may be NOT send the start signal to the starter motor, sort of like what would happen if we exceed the 999 miles to no start without adding DEF. But the dealer should be able to read the code that is stopping the computer from starting the car.


Turns out there was carbon dust on one of the pistons stopping it from turning over.


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## Diesel Power (Oct 2, 2010)

Diesel Power said:


> Sorry to hear that. Hope things turnout well for you.
> 
> My SA contacted me this morning and said my car was back together and running fantastic. They're going to keep the car another day to complete a few more test drives before releasing it. If all goes well, then tomorrow I'll be reunited will my 335d.
> 
> ...


Has everyone been on the edge of their seats waiting for my follow-up post? Well, here it is: the following morning the SES light triggered during the "final" test drive? Received the bad news and informed a PuMA case was opened. After several back and forth's with BMWNA, the DDE was flashed in an attempt to resolve the cylinder 3/injector fault code (remember what I said in a previous post?). After 100 miles of test drives, the dealer released the car to me today. The car ran great, just like when it was new. However, that was very short-lived. The SES light triggered again on the way home from the dealership. Went straight back to the dealer and got another loaner. Informed a short time later it was the same cylinder 3 injector fault code again. Hopefully, BMWNA will replace the DDE this time.


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## DieselRacer (Apr 22, 2014)

Seems like their taking care of it, this is a hit or miss car, its rather the best or it can be a nightmare, I have a great car now just fell in love with the 335d and I don't want to get rid of mine and get a bad bmw diesel.... anybody have any ballpark idea how many BMW sold of the 335d from 09 to 11...


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## Turbo_D (Aug 8, 2013)

http://ca.autoblog.com/2012/05/07/bmw-recalling-24-000-vehicles-over-emissions-problem/

according to this article, there's at least 21,000 335d's sold in NA.


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## quasimodem (Nov 9, 2011)

orbovi said:


> I bought mine CPO at 48k and had the warranty as well. Had carbon buildup but all covered under warranty with SES. Nothing to worry about.
> 
> Turns out there was carbon dust on one of the pistons stopping it from turning over.


Well, glad it is working, but carbon dust stopping the engine from turning over?


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## quasimodem (Nov 9, 2011)

DieselRacer said:


> Are there any high mileage 335d cars on here with high mileage that have not had this problem, anyone with high miles chime in...


I rolled 109k miles the other day, and just today I blasted a fifty-mile drive at between 65 and 90 mph because I was late for a hearing -- didnt have any problems. That being said, I have had a SES for the last errr 40k or so miles, the codes i found when I checked it in the beginning were 4804, 4A66, and 4B90. The 4B90 I believe to be something like "rail pressure control at start", 4A66 may have something to do with the battery/electrical system (I do have a couple of Amps hooked up directly to the battery), 4804 I have no idea... In the beginning the SES light would go on and off depending on whether the fuel tank was filled recently, so I wasnt worried about it, but now it is on all the time.  Regardless, it has been a great car and only weird thing I have seen was a cruise control failure notification a while back, but that stopped and it might have been related to the cold or weather.


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## DieselRacer (Apr 22, 2014)

I drive VW cr140's, 2009 and present engine, we remove all the exhaust from turbo back, flash the ecu for more power and tq and every time we pass emmisions in my state everyone who does it passes, I don't know of anyone with these mods falling yet...also we don't have problems with carbon build up in tdi's, yes they get carbon build up and some need to address it but it never disables the vehicle, the biggest problem with tdi;s is the hpfp, if it fails before 60k its a warranty fix, vw even takes care of dpf exhaust problems under warranty, something about federal exhaust laws...


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## Hoooper (Jun 17, 2013)

quasimodem said:


> Well, glad it is working, but carbon dust stopping the engine from turning over?


Sounds like they walnut blasted with a valve at least partially open :yikes:


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## kimbersc (Mar 6, 2013)

quasimodem said:


> Not turning over makes no sense. Maybe that is an incorrect description of the problem. The starter motor alone should be able to turn over the engine. I guess if there is some computer problem and the starter motor isnt being told to "engage" then it could be an electrical/computer problem otherwise it would be just a simple starter motor problem.
> 
> Come to think of it, something in the engine might not be working and, based on that failure, the computer may be NOT send the start signal to the starter motor, sort of like what would happen if we exceed the 999 miles to no start without adding DEF. But the dealer should be able to read the code that is stopping the computer from starting the car.





Hoooper said:


> Sounds like they walnut blasted with a valve at least partially open :yikes:


Yeah not quite sure how that happened to be honest


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## Diesel Power (Oct 2, 2010)

orbovi said:


> Yeah not quite sure how that happened to be honest


Inexperience or carelessness?


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## anE934fun (May 10, 2008)

Diesel Power said:


> Has everyone been on the edge of their seats waiting for my follow-up post? Well, here it is: the following morning the SES light triggered during the "final" test drive? Received the bad news and informed a PuMA case was opened. After several back and forth's with BMWNA, the DDE was flashed in an attempt to resolve the cylinder 3/injector fault code (remember what I said in a previous post?). After 100 miles of test drives, the dealer released the car to me today. The car ran great, just like when it was new. However, that was very short-lived. The SES light triggered again on the way home from the dealership. Went straight back to the dealer and got another loaner. Informed a short time later it was the same cylinder 3 injector fault code again. *Hopefully, BMWNA will replace the DDE this time*.


If they do, that will be a costly replacement.


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## kimbersc (Mar 6, 2013)

Diesel Power said:


> Inexperience or carelessness?


I'd say inexperience.


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## Dave @nz (May 13, 2007)

Hi,
My experience with Diesels stems from back in the 1990s back then in to New Zealand we had a lot of used import cars and diesels arriving from Japan some of the diesels had erg systems and nearly all of these if disassembled had blocked up intake manifolds and ports.

After cleaning out everything and re assembling:
How I fixed this problem from reoccurring was install a solid gasket (no hole in the middle) between the erg valve and the exhaust manifold it bolts to this stopping the exhaust gasses from entering the intake manifold.
By cleaning it out and re assembling all you are doing is delaying it happening again unless you block it off. Soot is a byproduct of diesel combustion it is in the exhaust gasses and the oil don't let it be drawn in to the intake. fyi I did the same to the petrol engines and they ran a lot better for it no surge or light throttle hesitation. 

Make no doubt about it this is The fix I cannot be clearer than that.

Dave.


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## Diesel Power (Oct 2, 2010)

Diesel Power said:


> Has everyone been on the edge of their seats waiting for my follow-up post? Well, here it is: the following morning the SES light triggered during the "final" test drive? Received the bad news and informed a PuMA case was opened. After several back and forth's with BMWNA, the DDE was flashed in an attempt to resolve the cylinder 3/injector fault code (remember what I said in a previous post?). After 100 miles of test drives, the dealer released the car to me today. The car ran great, just like when it was new. However, that was very short-lived. The SES light triggered again on the way home from the dealership. Went straight back to the dealer and got another loaner. Informed a short time later it was the same cylinder 3 injector fault code again. Hopefully, BMWNA will replace the DDE this time.


New DDE installed on Tuesday. Required an IRAP session for programming on Wednesday. Discovered SCR sensor fault on Thursday. Replacing DEF tank this upcoming Monday or Tuesday after part arrives. Hopefully, no additional problems. Looking forward to getting my 335d back.


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## anE934fun (May 10, 2008)

Diesel Power said:


> New DDE installed on Tuesday. Required an IRAP session for programming on Wednesday. Discovered SCR sensor fault on Thursday. Replacing DEF tank this upcoming Monday or Tuesday after part arrives. Hopefully, no additional problems. Looking forward to getting my 335d back.


Props to you for making the effort to get to a resolution. :thumbup: I hope there are no more SES/CEL lights and you can now enjoy the next life with your d. IMO, the 328d just doesn't compare with the 335d.


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## Diesel Power (Oct 2, 2010)

Thanks. Hope it's like my second marriage: much better than the first.


Sent from BimmerApp mobile app


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## Flyingman (Sep 13, 2009)

Diesel Power said:


> Thanks. Hope it's like my second marriage: much better than the first.
> 
> Sent from BimmerApp mobile app


+1:thumbup:


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## Flyingman (Sep 13, 2009)

I just got an EGR code, no SES. "Low Circulation Detected Circuit A." I seriously think I have carbon building up. I also got the low oil level light after about 6k since last oil change. I have not checked level since they changed it but it was on the low end of low today. I added 1 quart and it just went up to about 1/2 so I added a 2nd quart and it is full now. Seems like more oil than normal. My car had been using about 1 1/2 quarts per 13k miles. I suspect it was not topped off fully at last oil change.


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## greatamerican (May 2, 2014)

I am currently working this from Afghanistan. Here's to a good military wife! I'm out of warranty, but it looks like they're going to cover 80% of the cost and send the parts to Atlanta (probably to one of the places already mentioned). I have between 50-60k on my 2010 335d and sure I will have questions in the future. Especially once I hear their recommendations on how to go forward. Thanks for those of you who have contributed, this has been a big help. I'm pretty sure I'm #1 for this at my middle Georgia dealer.


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## anE934fun (May 10, 2008)

greatamerican said:


> I am currently working this from Afghanistan. Here's to a good military wife! I'm out of warranty, but it looks like they're going to cover 80% of the cost and send the parts to Atlanta (probably to one of the places already mentioned). I have between 50-60k on my 2010 335d and sure I will have questions in the future. Especially once I hear their recommendations on how to go forward. Thanks for those of you who have contributed, *this has been a big help*. I'm pretty sure I'm #1 for this at my middle Georgia dealer.


This is why I contribute where I can - to help others as I have been helped.

Hope you get to a successful resolution. It sounds like you and your wife are on the right trajectory.


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## BB_cuda (Nov 8, 2011)

Flyingman said:


> I just got an EGR code, no SES. "Low Circulation Detected Circuit A." I seriously think I have carbon building up. I also got the low oil level light after about 6k since last oil change. I have not checked level since they changed it but it was on the low end of low today. I added 1 quart and it just went up to about 1/2 so I added a 2nd quart and it is full now. Seems like more oil than normal. My car had been using about 1 1/2 quarts per 13k miles. I suspect it was not topped off fully at last oil change.


FM, how many miles now? I know you do a lot of highway driving. Not in anyway do I hope that you really do have CBU but if you do, I hoping its a high miles occurrence.

We have all commonly believed CBU is not an "if" but rather a "when" situation. City commuters will see it earlier and highway guys much later (hopefully),


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## Diesel Power (Oct 2, 2010)

New DEF tank installed. Finally got my 335d back today. All is well so far. I'll post a follow-up report in a week or so. I hope everyone else with a carbon buildup issue doesn't incur an out-of-pocket expense.


Sent from BimmerApp mobile app


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## Flyingman (Sep 13, 2009)

BB_cuda said:


> FM, how many miles now? I know you do a lot of highway driving. Not in anyway do I hope that you really do have CBU but if you do, I hoping its a high miles occurrence.
> 
> We have all commonly believed CBU is not an "if" but rather a "when" situation. City commuters will see it earlier and highway guys much later (hopefully),


Cuda,

just reaching 70k, 4 1/2 years on the car. I'm really hoping I'll get an SES as that would be the real trigger to bring in the car to service. Codes are indicative but aren't triggering any warnings. My MPG is consistently running about 2mpg below normal and I have a very steady commute routine, although I must say I think traffic has gotten worse and my commute time has increased these past few months.

Doubt the dealer is going to react to some thrown codes without an SES. They'll just reset them.


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## mrfeb14 (Jul 22, 2011)

*Finally back after 5 weeks*



Diesel Power said:


> New DEF tank installed. Finally got my 335d back today. All is well so far. I'll post a follow-up report in a week or so. I hope everyone else with a carbon buildup issue doesn't incur an out-of-pocket expense.


I just got mine back after 5 weeks at the dealer. First I had SES light and they changed the Mass Air Meter (expensive part that was), then 10 days later the light is back on right as the SIB for CBU was coming out. All repaired on BMW dime and during testing after the cleaning they got Active SCR Tank Fault and replaced that too.

I am so happy to have my car back after 5 weeks in a f30 320i loaner I want to drive everywhere. 

I really hope I don't see the SES light on for a long time.


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## n1das (Jul 22, 2013)

Hoooper said:


> The extreme example


That poor engine has never seen any boost.

It looks a lot like what older generation VW TDIs suffered from in the pre-ULSD days. Power and MPGs would suffer first, then the engine starts running poorly due to the intake restriction. The rate of intake clogging then accelerates exponentially due to the engine making more soot from running more poorly, when then causes more soot....etc.

It happened to me in a 2002 VW Golf TDI, but nowhere near as bad as in the extreme example. The intake was cleaned out and EGR was "modified" so that it would never have the problem again.

With VW TDIs, it's known that regularly driven them hard was effective at slowing the rate of clogging, assuming all stock hardware and functioning EGR. Driving the car hard would not reverse the clogging but definitely was effective at slowing the rate enough that you probably wouldn't need to clean it out. OTOH, things that contributed to clogging were: Short trips such that engine never reaches operating temp, short/early shifting causing lugging and more soot produced, idling for extended periods, and in general babying the engine and rarely or never getting on the power. VW TDI owners and enthusiasts like myself are serious when we recommend that you "Drive it like you stole it". That's how I drive my diesels.

I'm watching this thread with interest since I have a 2012 X5d (E70) w/57k miles (bought CPO used @ 52k miles) and a 2014 535d xDrive (F10). Currently at 57k miles on the E70 with no clogging issues.


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## Geotrash (Dec 22, 2013)

greatamerican said:


> I am currently working this from Afghanistan. Here's to a good military wife!


Thank you, thank you, thank you for your service. I'm grateful for it for many reasons, but at this moment because yours and the service of others makes it possible for us to enjoy both our cars and this discussion freely.

Sent from BimmerApp mobile app


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## mrfeb14 (Jul 22, 2011)

mrfeb14 said:


> I really hope I don't see the SES light on for a long time.


Well that didn't last long. 6 days after getting my car back the SES light is back on  Back to the dealer I go today. Hopefully it won't be another long term stay.


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## floydarogers (Oct 11, 2010)

mrfeb14 said:


> Well that didn't last long. 6 days after getting my car back the SES light is back on Back to the dealer I go today. Hopefully it won't be another long term stay.


BUMMER!

Kind of affirms my contention that many BMW techs don't know what they're doing on these diesels.


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## n1das (Jul 22, 2013)

floydarogers said:


> BUMMER!
> 
> Kind of affirms my contention that many BMW techs don't know what they're doing on these diesels.


That dealer is probably not doing the owner any favors.

It sounds a lot like VW dealer service departments and dealing with the TDI models. They're incompetent when it comes to the diesel models. Their solution is to simply throw parts at it at the customer's expense until the problem goes away. They have trouble doing oil changes correctly and using the correct TDI-specific oil. It makes it hard to trust them for major service like a timing belt change, of which they are famous for screwing up and eventually trashing someone's engine. In the case of owning a VW TDI, you're better off to take matters into your own hands and stay away from the dealer. That means doing the routine maintenance yourself and going to one of many TDIclub.com (www.TDIclub.com) GURUs in your area for major work. VW's "care free" maintenance during the warranty period really isn't care-free after all.

I've owned 3 VW TDI models over the past 13 years and have logged more than 500k miles while owning them. (Read: I drive a lot!) I've avoided dealer service from close to day 1 and have done my own routine maintenance. Note you do not void any warranties by DIY for maintenance provided the work is done correctly (Magnusson-Moss Warranty Act of 1975). For major stuff that I can't do myself, I go to a local TDI guru in my area. He is an excellent independent mechanic and a VW/Audi expert. He will work on anything, VW/Audi is his specialty, and the diesels are his favorites. He also works on BMWs too. This is the kind of independent mechanic anybody frustrated with BMW service might want to seek out. Find an independent mechanic that knows what he's doing and really KNOWS these cars.

To address CBU in a BMW diesel, long term you might be better off to DIY.

Good luck.


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## Diesel Power (Oct 2, 2010)

mrfeb14 said:


> Well that didn't last long. 6 days after getting my car back the SES light is back on  Back to the dealer I go today. Hopefully it won't be another long term stay.


If it's a cylinder/injector 3 fault, then the DDE will most likely need to be replaced. How many miles did the dealer test drive your vehicle after performing the SIB for carbon?


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## mrfeb14 (Jul 22, 2011)

Diesel Power said:


> If it's a cylinder/injector 3 fault, then the DDE will most likely need to be replaced. How many miles did the dealer test drive your vehicle after performing the SIB for carbon?


37 miles were added to the car when I picked it up. I have driven about 520 miles since last week when I got it back.


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## davinci74 (Jun 4, 2012)

I bought my 335d used about a year and half ago. It now has 83k miles and I absolutely love it, but reading threads like these scare the hell out of me. There has to be a better way to prevent carbon build up. I drive a lot of highway miles and I used to baby my car, but I used to get the SES light every so often. The car also went into limp mode once after driving it on a very cold January day. After reading a few posts that the diesel must be driven hard, I began flooring it from 20 MPH off a ramp for 2 shifts up to 80 MPH ever single night coming home from work. While it is fun to do, and it has solved my SES light problem, but the entire situation just isn't not right... I'm not going to want to spend thousands of dollars to clean the heads of a 100k mile old engine. It feels like driving a ticking time bomb.


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## mrfeb14 (Jul 22, 2011)

mrfeb14 said:


> 37 miles were added to the car when I picked it up. I have driven about 520 miles since last week when I got it back.


Just got it back. This time scr metering valve and nox sensors.


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## KeithS (Dec 30, 2001)

davinci74 said:


> I bought my 335d used about a year and half ago. It now has 83k miles and I absolutely love it, but reading threads like these scare the hell out of me. There has to be a better way to prevent carbon build up. I drive a lot of highway miles and I used to baby my car, but I used to get the SES light every so often. The car also went into limp mode once after driving it on a very cold January day. After reading a few posts that the diesel must be driven hard, I began flooring it from 20 MPH off a ramp for 2 shifts up to 80 MPH ever single night coming home from work. While it is fun to do, and it has solved my SES light problem, but the entire situation just isn't not right... I'm not going to want to spend thousands of dollars to clean the heads of a 100k mile old engine. It feels like driving a ticking time bomb.


I think we can all rest a little easier now that they have the kit to do the walnut basting of the head in place. While no one had had to pay for this yet, and it probably will cost more than $1000, I think the first digit will still be a 1. At least it's not $10,000 as the old cleaning method was when the head had to be removed. The gas engine also suffers from carbon build up, as it seems to impact all direct injected engines. Now we are at least in the same ball park as the gassers.


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## Frediesel (Apr 28, 2012)

I emailed BMW Worx (So Cal Indy) with the SIB on the walnut blasting diesel procedure. I remember watching a YouTube video where they performed walnut blasting on a gasser. They said they would let me know shortly after looking into it. I suggest others who would do this before codes are thrown or who are out of warranty do the same in your area.


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## DaveN007 (Oct 4, 2013)

Frediesel said:


> I emailed BMW Worx (So Cal Indy) with the SIB on the walnut blasting diesel procedure. I remember watching a YouTube video where they performed walnut blasting on a gasser. They said they would let me know shortly after looking into it. I suggest others who would do this before codes are thrown or who are out of warranty do the same in your area.


+1

They key is to do this BEFORE you find yourself in code hell. Otherwise the swaptronics begins.

These cars are designed to be serviced while under warranty by swapping parts based upon codes. Labor is expensive.


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## Flyingman (Sep 13, 2009)

Frediesel said:


> I emailed BMW Worx (So Cal Indy) with the SIB on the walnut blasting diesel procedure. I remember watching a YouTube video where they performed walnut blasting on a gasser. They said they would let me know shortly after looking into it. I suggest others who would do this before codes are thrown or who are out of warranty do the same in your area.


I emailed the SIB to my local Indy Shop and he said he was not set up to do the walnut blasting as he did not have enough demand to warrant the investment. He still is suggesting to use a liquid cleaning, use of various sprays as we have seen advertised.

I'll have a long discussion with my local BMW Service Manager at next scheduled service and get a definitive answer to if and when they can do it, under what conditions is it warranted, and/or at what estimated cost.

I still have 30k miles or 1 1/2 years on my extended warranty so if CBU pops up, and I suspect it will, I'll be banging on their door.


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## Geotrash (Dec 22, 2013)

Flyingman said:


> I emailed the SIB to my local Indy Shop and he said he was not set up to do the walnut blasting as he did not have enough demand to warrant the investment. He still is suggesting to use a liquid cleaning, use of various sprays as we have seen advertised.


You could also probably outsource the walnut shell blasting process itself to a shop that has the equipment. Your Indie shop could do the teardown and prep work, then either you or they can take the head to the other shop for cleaning.

Cheers,
Dave


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## Flyingman (Sep 13, 2009)

Dave,

You need to read the SIB. This is an in place cleaning so you don't have to remove the head which is what was making the cost of cleaning so expensive.

BMW already does walnut blasting on the gas injected engines to remove CBU. All they had to do was design some different sizes and shapes of wands in order to get into the more intricate areas of the 335D intake area.

The option of removing the head is always available but a rather expensive one. Perhaps $8k vs $1k -$2k based on what I've been able to determine so far.

No one has yet to post how much the walnut cleaning as per the SIB costs.


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## MotoWPK (Oct 5, 2012)

There are a number of misconceptions regarding carbon build up and engine loading. One of them is the idea that high power loading will burn off the carbon. This misconception likely stems from high power being effective, to some degree, in reducing or burning off in cylinder carbon build up. The primary carbon build up of concern with modern diesels is not in the cylinder, but in the intake track (intake manifold and cylinder head intake ports). No amount of engine loading is going to burn this off - the temperatures in the intake simply do not reach a level that will burn off carbon.

The carbon build up issue with modern diesels results from exhaust gas re-circulation and has nothing to do, as was suggested, with more or less fuel in the EGR, but with carbon that results from incomplete combustion of the carbon in diesel fuel (don't confuse incomplete combustion here with raw fuel in the exhaust - virtually all the fuel has undergone some degree of combustion and the carbon present in the exhaust is from fuel molecules that have been broken down by combustion but some of the carbon molecules therein not having been oxidized).

While lesser amounts of EGR is needed at higher loads, the reduction is not nearly as great as the amount of increased fuel at higher loads and, corresponding to the lower air/fuel ratio at higher loads, the amount of un-oxidized carbon; i.e. soot.

Ultimately, it's not a matter of the percent EGR present, but the absolute amount of carbon being recirculated from the exhaust to the intake and that carbon's tendency to condense on the surfaces of the intake system. Higher engine loads will definately increase the amount of carbon recirculated to the intake. As to it's tendency to condense, that's more complicated. It is at a higher temperature, at higher load, but all BMW's (indeed I believe all modern diesels) have EGR coolers to reduce the temperature of the recirculated exhaust gas. Whether increasing load to some point raises the recirculated exhaust to a point above the condensing temperature of the carbon is unknown (at least by me).

What is clear is that lighter loads result in less carbon, soot, in the exhaust and at least from that standpoint would reduce carbon build up.


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## tonyspumoni (May 23, 2010)

MotoWPK,

Terrific post. I'll use this as a reference in the future. I wasn't at all thinking that high loading would burn off carbon build-up - more that this would result in more complete combustion of fuel present. Without question this view draws on any number of possibly bad assumptions. For starters fuel:air ratios are not at all constant, I've been lead to believe, so EGR activity may be quite different regardless of loading.

It sure would be useful to get some of BMW's data on this as they would surely have assessed the amount of unburned fuel passing to the EGR at every loading level and under most conditions - they would had to have done this in order to properly set fuel:air mixes.

I can tell you this though for certain, I had no CBU and I drove these cars just about as hard as they can be driven. I managed to burn off four sets of tires in just over 70k of total driving - yep - total douche. But a douche with style.


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## Smplife (Jul 9, 2014)

I heard that BMW has recalled some diesels to correct emission issues. 

Does that address the CBU design problem?

Another question: most of us are protected against the CBU problem by our warranty. But warranty eventually runs out. If BMW does not have a fix for their design problem, we have to keep on buying warranty or expect to pay big repair bills for their error. What remedy do we consumers have?

Thanks


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## F32Fleet (Jul 14, 2010)

Smplife said:


> I heard that BMW has recalled some diesels to correct emission issues.
> 
> Does that address the CBU design problem?
> 
> ...


There was an EGR recall a few years ago and it also required new programming. I know some owners complained of reduced MPG's after the work was done. IF the new programming resulted in more soot via EGR that may explain why some cars had premature build up and would also explain the drop in MPG.

Also around or before that time an owner complained that his car would not pass emissions. It was odd because the car was less than 2 yrs old and he never answered why he was having the car tested to begin with.

I'm not sure I would call it a design problem. I would call it a improper match of engine with the intended operating environment. Just like BMW gassers there is no fix. Just have the carbon cleaned whenever you start having drivability problems.

My own personal opinion is that BMW had to turn up the EGR in order to meet emissions and along with less than ideal fuel, city drivers developed problems with excess carbon. I drive mostly Hwy at ~2k rpms and my mpg's have been steady for 65k miles which means I'm not having major problems with CBU.


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## nuclearbeef (Dec 19, 2012)

I'm no engineer, so someone with more knowledge, please enlighten me if I'm laboring under any misconceptions.

Gasoline engines operate at a fixed air/fuel ratio (AFR). Power is regulated by changing the amount of fuel/air mixture entering the cylinder. 

Diesel engines operate at varying AFRs. Power is regulated by changing the amount of fuel introduced into a fixed amount of air in the cylinder. (Simplification assuming NA engine at constant RPM)

Right?


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## KeithS (Dec 30, 2001)

Correct! Diesel has excess air in the combustion process. Which is exactly why it produces so much NOx that needs to be taken out to meet pollution standards.


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## MotoWPK (Oct 5, 2012)

nuclearbeef said:


> I'm no engineer, so someone with more knowledge, please enlighten me if I'm laboring under any misconceptions.
> 
> Gasoline engines operate at a fixed air/fuel ratio (AFR). Power is regulated by changing the amount of fuel/air mixture entering the cylinder.
> 
> ...


Correct, with the qualification that air flow in diesel engines varies with engine speed and for gas engines it varies with engine speed and throttling.

While gas engines operate near stochiometric air/fuel ratio (~14.7 lb air / lb fuel) regardless of load, diesel engines operate at very lean ratios at low load, up to about 50:1 at idle. Soot production is thus lower at low loads due to the large amount of excess air, promoting more complete combustion of the fuel.

Related, particulate filter (DPF) passive regeneration is maximized by running the engine at modest load, providing an optimal combination of low soot production and sufficient exhaust temperature to burn off soot accumulated in the DPF.

Low soot production is clearly advantageous to reducing carbon build up in the intake, due to exhaust gas recirculation, though the picture is complicated by the fact that a greater amount of exhaust gas must be recirculated (as a percentage of intake flow) at lower loads, though this appears to be a smaller effect than the lower soot production rate at low loads.

It's a bit counter intuitive that lower loads produce more NOx, as a percentage of fuel flow (i.e. lb NOx / lb fuel). While overall combustion temperatures are higher at higher loads, the greater amount of excess air at lower load results in higher localized or peak combustion temperatures, and it is the peak combustion temperatures that create NOx.


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## magbarn (Jan 28, 2003)

MotoWPK said:


> Correct, with the qualification that air flow in diesel engines varies with engine speed and for gas engines it varies with engine speed and throttling.
> 
> While gas engines operate near stochiometric air/fuel ratio (~14.7 lb air / lb fuel) regardless of load, diesel engines operate at very lean ratios at low load, up to about 50:1 at idle. Soot production is thus lower at low loads due to the large amount of excess air, promoting more complete combustion of the fuel.
> 
> ...


What I don't understand is that our 3.0L engines do so much better in a heavier loaded application like the X5, whilst 335d's are the ones dropping like flies from emission issues that don't seem to bother the X5 at all?


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## MotoWPK (Oct 5, 2012)

magbarn said:


> What I don't understand is that our 3.0L engines do so much better in a heavier loaded application like the X5, whilst 335d's are the ones dropping like flies from emission issues that don't seem to bother the X5 at all?


The engines, and their emissions systems, are not identical. For example, where the 335d had one EGR the E70 35d has two, one being upstream of the DPF, as with the 335d, and one downstream of the DPF. The EGR downstream of the DPF is thus recirculating exhaust that has had soot removed by the DPF and, to the degree soot is removed and depending on the flow split between the two EGR's, would result in less soot being recirculated back to the intake.

That's only one obvious difference. There are likely numerous other differences in the control specifics between the two vehicles and, I would expect, further differences to the current model years.

Likely nobody outside of BMW really knows, and they aren't saying, but I suspect those differences are more important than engine loading differences between the 335d and X5 35d.


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## magbarn (Jan 28, 2003)

MotoWPK said:


> The engines, and their emissions systems, are not identical. For example, where the 335d had one EGR the E70 35d has two, one being upstream of the DPF, as with the 335d, and one downstream of the DPF. The EGR downstream of the DPF is thus recirculating exhaust that has had soot removed by the DPF and, to the degree soot is removed and depending on the flow split between the two EGR's, would result in less soot being recirculated back to the intake.
> 
> That's only one obvious difference. There are likely numerous other differences in the control specifics between the two vehicles and, I would expect, further differences to the current model years.
> 
> Likely nobody outside of BMW really knows, and they aren't saying, but I suspect those differences are more important than engine loading differences between the 335d and X5 35d.


In other words, block the EGR, have a scangauge tool ready to clear all the codes with each startup, and when smog check time comes, remove the block and clear the codes... :bawling:


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## FredoinSF (Nov 29, 2009)

magbarn said:


> In other words, block the EGR, have a scangauge tool ready to clear all the codes with each startup, and when smog check time comes, remove the block and clear the codes... :bawling:


History repeating itself. It's the 70's all over again.

Totally off topic: Had a look at the pictures of your car and that is one stunning color combo. You have of the nicest E90's I've ever seen. Wow.


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## Blackfly (Nov 10, 2010)

*Carbon buildup?.*

This seems to be the topic du Jour on this board.

I had the EGR replaced under a campaign shortly after taking delivery of my 2011 in November 2010. No significant issues after that. No Christmas tree lights in the dash. Zero. I'm also under the impression that climate has little to do with this.

I would like to see how many 335d models were delivered in the US vis a vis actual problems. It seems there are less complaints than this forum (based on posts) would have you believe.

In true BMW fashion, it is unlikely we will ever know these numbers. It maybe time to trade up to a 335i M-Sport Sedan...

Just sayin'

BlackFly


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## tonyspumoni (May 23, 2010)

Perhaps you are right. I would suggest though that reporting of these problems underrepresents the number of genuine troubles. Most 335d owners do not post here. A casual seach of other forums for diesels - the TDI forums on VWvortex - does not reveal a high frequency of posts devoted to emissions issues. And when these issues do occur in the 335d they are not always (or even often) resolved simply and durably, suggesting systematc rather than stochastic causes. I am not being critical of your views in any way - I wish you the very best of luck. 


Sent from BimmerApp mobile app


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## imtjm (Oct 5, 2004)

tonyspumoni said:


> Perhaps you are right. I would suggest though that reporting of these problems underrepresents the number of genuine troubles. Most 335d owners do not post here. A casual seach of other forums for diesels - the TDI forums on VWvortex - does not reveal a high frequency of posts devoted to emissions issues. And when these issues do occur in the 335d they are not always (or even often) resolved simply and durably, suggesting systematc rather than stochastic causes. I am not being critical of your views in any way - I wish you the very best of luck.
> 
> Sent from BimmerApp mobile app


Not to mention the number of reported issues was significant enough for BMW to self-recall 335d in 2011-2012 for the emissions issues.


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## imtjm (Oct 5, 2004)

Blackfly said:


> I would like to see how many 335d models were delivered in the US vis a vis actual problems. It seems there are less complaints than this forum (based on posts) would have you believe.
> BlackFly


i would say the opposite is true, given BMW's self-recall of the 335d for the emissions issue.


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## ChasR (Aug 29, 2012)

At 89K miles, I've joined the CBU club. $2800 to clean the CBU and replace 2 injectors.


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## tonyspumoni (May 23, 2010)

ChasR said:


> At 89K miles, I've joined the CBU club. $2800 to clean the CBU and replace 2 injectors.


Sorry ChasR, that sucks. I still miss mine but feared to follow in your footsteps eventually. Still, if that fixes the troubles for another 89k miles, I guess $2800 would be a great deal.

The thing that kills me is that other than a sticky sunroof, everything else on my two 335d's worked perfectly. Every problem I can remember having was emissions related. If a car is just poorly engineered all around and stuff of all kinds breaks, that almost makes it easier to cut and run. But when it is just one facet, we always tend to say "if I just fix this, THEN it'll be the perfect car."

There is no right answer on when to ditch a car and I'm the last guy to be critical of anyone else's value-based choices. But did your SA give you a reason while you won't be looking at the other four injectors soon? I'd be worried that that two will turn to four more.


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## F32Fleet (Jul 14, 2010)

imtjm said:


> i would say the opposite is true, given BMW's self-recall of the 335d for the emissions issue.


Recalls happen all the time. EGR and programming were done. Nothing out of the ordinary there.


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## Blackfly (Nov 10, 2010)

*No Warranty Coverage*

Being spooked slightly by the anti-carbon thread, i was prompted to have a discussion with my Local dealer.

I asked specifically about warranty coverage againtst repairs to the CBU debacle. The only (BMW) dealer in Maine sold only 4 335 diesels in three years of production, only one built to order, mine. I learned that the emissions coverage is a Federal program with a duration of 8 years and/or 80k miles, whichever comes first. According to the dealer, it does not cover 'coking' of the cylinder heads. I explained that the EGR valve had been replaced on a campaign no more than 3k into my clock and she said that was covered under the standard warranty program and is not covered under the 8/80 program if presented as a normal warranty item repair. Goodwill only.

I then asked "What about the BMW warranty program? In my case, I'm considering the 'Gold' program with coverage to 7 years and 100k miles. Nope. Not covered. WTF! You mean I spend $3900 for supplemental coverage and it DOES NOT cover premature failure due to cylinder excess carbon deposits?

A warranty program for a modest extension of time and mileage and no coverage for a 'coked' 4 year old BMW. I ran the calcs on the mentioned Gold package and as near as I can tell, BMW expects to spend up to $2000 for that period of time from the expiration of the regular warranty and the end of the optional package on claims. The rest is margin.

So, the decision whether to buy additional warranty coverage is easy.

If my Christmas Tree lights up, I'll just call the Local Indie shop. and, there are two real good ones within spitting distance.

Good luck squeezing blood from a stone.

Best,

BlackFly


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## F32Fleet (Jul 14, 2010)

Blackfly said:


> Being spooked slightly by the anti-carbon thread, i was prompted to have a discussion with my Local dealer.
> 
> I asked specifically about warranty coverage againtst repairs to the CBU debacle. The only (BMW) dealer in Maine sold only 4 335 diesels in three years of production, only one built to order, mine. I learned that the emissions coverage is a Federal program with a duration of 8 years and/or 80k miles, whichever comes first. According to the dealer, it does not cover 'coking' of the cylinder heads. I explained that the EGR valve had been replaced on a campaign no more than 3k into my clock and she said that was covered under the standard warranty program and is not covered under the 8/80 program if presented as a normal warranty item repair. Goodwill only.
> 
> ...


#1 shop around on the OEM warranty. Your price is high.

#2 CBU issues are not guaranteed to happen under X miles. While the extended warranty probably will not cover CBU cleaning now that there's a cheaper way of having it done it WILL cover injectors and emissions system issues. For example, I've had significant work done on my SCR system all under an extended warranty. (2 NOX sensors, Control Module, Urea Tank(2x), New SCR catalyst,). Parts alone were ~$4,000. The math says I'm ahead.

People need to stop with this obsession over CBU.


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## Diesel Power (Oct 2, 2010)

I did some "soul searching" after getting my 2011 335d back from CBU with a new DDE and DEF tank installed. Decided to keep my car for at least two more years. The 100K Platinum Extended Warranty provides some level of reassurance. If I go longer than a two year period, then I have no doubt another cleaning will be needed.


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## floydarogers (Oct 11, 2010)

Blackfly said:


> ...So, the decision whether to buy additional warranty coverage is easy.


I just wanted to mention that, although apparently extended BMW warranty doesn't cover it (explicitly), CPO does - the SIB says so.



BMWTurboDzl said:


> ...People need to stop with this obsession over CBU.


I agree.:thumbup:


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## anE934fun (May 10, 2008)

BMWTurboDzl said:


> #1 shop around on the OEM warranty. Your price is high.
> 
> #2 CBU issues are not guaranteed to happen under X miles. While the extended warranty probably will not cover CBU cleaning now that there's a cheaper way of having it done it WILL cover injectors and emissions system issues. For example, I've had significant work done on my SCR system all under an extended warranty. (2 NOX sensors, Control Module, Urea Tank(2x), New SCR catalyst,). Parts alone were ~$4,000. The math says I'm ahead.


Extended warranty coverage is something of a variable, depending on state regulation. In CA, extended warranty plans sold in-state are subject to regulation by the state dept. of insurance. If the codes are being thrown, the policy will cover the cleaning along with other part replacement (fuel injectors, DME, etc.) until codes are not being thrown. You may have to go back to the dealer multiple times to get everything sorted out, but the policy will end up covering the cost of the repairs. I have personal experience in this regard with an EasyCare Gold extended warranty for suspension repairs on a non-BMW I own.

If my 335d is throwing codes, I am quite certain the Allstate extended warranty policy that I purchased for the d will be picking up the cost.

The unknown is what to do about the symptoms leading up to codes being thrown. I might be thinking about doing a prophylactic cleaning of the intake per the SIB to avoid the aggravation further down the line. Then, I doubt the expense would be covered by the extended warranty policy.

Decisions, decisions, decisions.



> People need to stop with this obsession over CBU.


+1.


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## tonyspumoni (May 23, 2010)

Too late did I discover GEICO's mechanical breakdown coverage. Though there is a $250 deductible, must be started when the vehicle is new, and only goes to 100k miles, it covers everything insofar as I can tell. Sounds like Allstate has something similar. Never another extended warranty for me. 


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## Pierre Louis (Oct 23, 2011)

tonyspumoni said:


> Never another extended warranty for me.


Does this mean you will never own a car past warranty, think the cost is too much compared to the risk, only buy "reliable cars", or something else?

PL


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## n1das (Jul 22, 2013)

MotoWPK said:


> There are a number of misconceptions regarding carbon build up and engine loading. One of them is the idea that high power loading will burn off the carbon. This misconception likely stems from high power being effective, to some degree, in reducing or burning off in cylinder carbon build up. The primary carbon build up of concern with modern diesels is not in the cylinder, but in the intake track (intake manifold and cylinder head intake ports). No amount of engine loading is going to burn this off - the temperatures in the intake simply do not reach a level that will burn off carbon.
> 
> The carbon build up issue with modern diesels results from exhaust gas re-circulation and has nothing to do, as was suggested, with more or less fuel in the EGR, but with carbon that results from incomplete combustion of the carbon in diesel fuel (don't confuse incomplete combustion here with raw fuel in the exhaust - virtually all the fuel has undergone some degree of combustion and the carbon present in the exhaust is from fuel molecules that have been broken down by combustion but some of the carbon molecules therein not having been oxidized).
> 
> ...


Lighter loads unfortunately also result in higher EGR rates which will add to CBU.

The "drive it like you stole it" recommendation comes from comes various owner experiences dealing with CBU in BMWs and other diesels.

Driving the car hard and loading up and working the engine hard keeps the turbo "on boost". The higher RPMs while loaded also greatly increase the flow through the intake system. It's the combination of BOOST and FLOW through the intake manifold that seems to help slow the rate of CBU.


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## magbarn (Jan 28, 2003)

Pierre Louis said:


> Does this mean you will never own a car past warranty, think the cost is too much compared to the risk, only buy "reliable cars", or something else?
> 
> PL


Why I decided to skip and gamble past the buying window on BMW's extended warranty is their crazy exclusions. For the exorbitant prices their charging for platinum extended warranty, CBU service should be included. Case in point, I don't know if its just a reflection of superior reliability or Acura has better underwriters, but I can easily get a 8 year/120,000 mile extended warranty from Acura on my parents TL in the $2000's and pretty much the only excluded items are interior rattles and wear and tear. The drive train is fully covered other than routine maintenance.


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## Pierre Louis (Oct 23, 2011)

magbarn said:


> Why I decided to skip and gamble past the buying window on BMW's extended warranty is their crazy exclusions. For the exorbitant prices their charging for platinum extended warranty, CBU service should be included. Case in point, I don't know if its just a reflection of superior reliability or Acura has better underwriters, but I can easily get a 8 year/120,000 mile extended warranty from Acura on my parents TL in the $2000's and pretty much the only excluded items are interior rattles and wear and tear. The drive train is fully covered other than routine maintenance.


The high cost of dealer service at BMW may be reflected in the price. This is a calculation that BMW seems to have done and part of their image in the US as a rival to Mercedes. Of course BMW's technical complexity compares to even more expensive brands.

PL


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## F32Fleet (Jul 14, 2010)

magbarn said:


> Why I decided to skip and gamble past the buying window on BMW's extended warranty is their crazy exclusions. For the exorbitant prices their charging for platinum extended warranty, CBU service should be included. Case in point, I don't know if its just a reflection of superior reliability or Acura has better underwriters, but I can easily get a 8 year/120,000 mile extended warranty from Acura on my parents TL in the $2000's and pretty much the only excluded items are interior rattles and wear and tear. The drive train is fully covered other than routine maintenance.


CBU isn't covered on BMW's gassers and they need to be done at about every 60k miles or less so why should the 335d be different ?


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## magbarn (Jan 28, 2003)

BMWTurboDzl said:


> CBU isn't covered on BMW's gassers and they need to be done at about every 60k miles or less so why should the 335d be different ?


They should be covered too AFAIK, the 335i extended warranty rates are pretty much on par to the 335d's.


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## ChasR (Aug 29, 2012)

tonyspumoni said:


> Sorry ChasR, that sucks. I still miss mine but feared to follow in your footsteps eventually. Still, if that fixes the troubles for another 89k miles, I guess $2800 would be a great deal.
> 
> The thing that kills me is that other than a sticky sunroof, everything else on my two 335d's worked perfectly. Every problem I can remember having was emissions related. If a car is just poorly engineered all around and stuff of all kinds breaks, that almost makes it easier to cut and run. But when it is just one facet, we always tend to say "if I just fix this, THEN it'll be the perfect car."
> 
> There is no right answer on when to ditch a car and I'm the last guy to be critical of anyone else's value-based choices. But did your SA give you a reason while you won't be looking at the other four injectors soon? I'd be worried that that two will turn to four more.


I looked at the estimate more closely and find they aren't replacing any injectors. I expect I'll be having injector codes pop up in the near future.


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## magbarn (Jan 28, 2003)

ChasR said:


> I looked at the estimate more closely and find they aren't replacing any injectors. I expect I'll be having injector codes pop up in the near future.


So the question of the day is: Would doing a CBU service BEFORE SES lights come on/power loss hits prevent the need for expensive injector replacement?


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## ChasR (Aug 29, 2012)

Got the car back yesterday. Runs OK, but it still has a rough idle, exactly as it did when I brought it in. When I cleared the injector 6 code before, it took 1000 miles for it to come back. I suspect it will be back. My own theory on one of the possible causes of CBU is worn injectors. As the injectors wear, the combustion process produces more soot, which gets dumped into the intake by EGR. BY the time the injectors start to throw codes, you've got CBU.


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## F32Fleet (Jul 14, 2010)

ChasR said:


> Got the car back yesterday. Runs OK, but it still has a rough idle, exactly as it did when I brought it in. When I cleared the injector 6 code before, it took 1000 miles for it to come back. I suspect it will be back. My own theory on one of the possible causes of CBU is worn injectors. As the injectors wear, the combustion process produces more soot, which gets dumped into the intake by EGR. BY the time the injectors start to throw codes, you've got CBU.


Inadequate detergents in the fuel perhaps?


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## Pierre Louis (Oct 23, 2011)

Anyone here ever tried BG to prevent carbon fouling?


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## ChasR (Aug 29, 2012)

I'm thinking about methanol injection to prevent CBU.


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## totitan (May 11, 2013)

Pierre Louis said:


> Anyone here ever tried BG to prevent carbon fouling?


An acquaintance of mine from Europe owns one of the most successfull independent german car repair shops in Ventura County. Last week I asked him about the cbu/injector issue. He gave me a quart of Wurth Diesel Injector Cleaner and Cetane Boost (Art.No. 0893 0000 354-U) and said that it is the best product avaliable for keeping diesel injectors clean. The label indicates that 32 Oz will treat 300 gallons.

I have no idea what it costs or even where to buy it, but wanted to pass it on as a fyi.


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## Pierre Louis (Oct 23, 2011)

totitan said:


> An acquaintance of mine from Europe owns one of the most successfull independent german car repair shops in Ventura County. Last week I asked him about the cbu/injector issue. He gave me a quart of Wurth Diesel Injector Cleaner and Cetane Boost (Art.No. 0893 0000 354-U) and said that it is the best product avaliable for keeping diesel injectors clean. The label indicates that 32 Oz will treat 300 gallons.
> 
> I have no idea what it costs or even where to buy it, but wanted to pass it on as a fyi.


I've used Wurth products for years and love them!

Can't seem to find this stuff on the Internet. I've contacted a buddy of mine that may be able to get it.

Thanks!

PL


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## totitan (May 11, 2013)

Pierre Louis said:


> I've used Wurth products for years and love them!
> 
> Can't seem to find this stuff on the Internet. I've contacted a buddy of mine that may be able to get it.
> 
> ...


Pierre Louis I just noticed "for professional use only" printed on the label so you will probably have to find a shop willing to sell it to you. If that fails, PM me and I'll try to hook you up


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## Pierre Louis (Oct 23, 2011)

totitan said:


> Pierre Louis I just noticed "for professional use only" printed on the label so you will probably have to find a shop willing to sell it to you. If that fails, PM me and I'll try to hook you up


Thanks.

I'll try to keep looking around here - maybe ask my private mechanic.

PL


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## F32Fleet (Jul 14, 2010)

totitan said:


> An acquaintance of mine from Europe owns one of the most successfull independent german car repair shops in Ventura County. Last week I asked him about the cbu/injector issue. He gave me a quart of Wurth Diesel Injector Cleaner and Cetane Boost (Art.No. 0893 0000 354-U) and said that it is the best product avaliable for keeping diesel injectors clean. The label indicates that 32 Oz will treat 300 gallons.
> 
> I have no idea what it costs or even where to buy it, but wanted to pass it on as a fyi.


Looks similar to Lubro Moly Products.


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## ChasR (Aug 29, 2012)

Yesterday, the SES light came back on, injector 3 zero adaptation, smooth running and camshaft sensor codes. Cleaning out the carbon didn't improve the rough idle or decreased fuel mileage a bit. I'm feeling screwed.


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## Pierre Louis (Oct 23, 2011)

BMWTurboDzl said:


> Looks similar to Lubro Moly Products.


Could be. Lubro-Moly and Liqui-Moly I believe are the same brand.

Here it shows that its not compatible with the 335d. Sigh.

PL


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## Blackfly (Nov 10, 2010)

*Wurth additive*



totitan said:


> An acquaintance of mine from Europe owns one of the most successfull independent german car repair shops in Ventura County. Last week I asked him about the cbu/injector issue. He gave me a quart of Wurth Diesel Injector Cleaner and Cetane Boost (Art.No. 0893 0000 354-U) and said that it is the best product avaliable for keeping diesel injectors clean. The label indicates that 32 Oz will treat 300 gallons.
> 
> I have no idea what it costs or even where to buy it, but wanted to pass it on as a fyi.


The local Wurth distributor to me is a mobile guy. I just placed an order for a 12 QT case lot. The price: $15.61/EA plus transport. Closest warehouse to me in NE is NJ.

BF


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## Nadir Point (Dec 6, 2013)

The injector issue is separate but related to CBU. Diesel injectors die prematurely due to several causes. The biggest problem these days is lower lubricity of commonly available ULSD fuel. Excessive crap coming through the intake causes accelerated fouling after they start leaking from wear. Fuel mileage is the big tell.


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## anE934fun (May 10, 2008)

Nadir Point said:


> The injector issue is separate but related to CBU. Diesel injectors die prematurely due to several causes. *The biggest problem these days is lower lubricity of commonly available ULSD fuel*. Excessive crap coming through the intake causes accelerated fouling after they start leaking from wear.


I have been thinking this may be a root cause to the CBU as well. If the theory is correct, there should be lower instances of CBU in the eurozone d cars (better lubricity of euro D2). Does anyone have access to data regarding CBU in the eurozone?



> Fuel mileage is the big tell.


How so? Injector wear resulting in lower mileage? Or?


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## totitan (May 11, 2013)

anE934fun said:


> I have been thinking this may be a root cause to the CBU as well. If the theory is correct, there should be lower instances of CBU in the eurozone d cars (better lubricity of euro D2). Does anyone have access to data regarding CBU in the eurozone?
> 
> How so? Injector wear resulting in lower mileage? Or?


For what it's worth:
I bought my car in March of 13 with 33000 miles on on it. I have added 1/4 oz/gal of Optilube XPD (best additive for increasing lubricity to European standards) every time I have fueled the car. The car now has 60000 miles on it and has not shown any signs of cbu. No SES light, still averaging 34 mpg, idle is smooth, and the power is still phenomenal.

I'm not trying to prove anything here......simply presenting the facts regarding my efforts to supply my 335d with a constant supply of European spec fuel lubricity.


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## anE934fun (May 10, 2008)

totitan said:


> For what it's worth:
> I bought my car in March of 13 with 33000 miles on on it. I have added 1/4 oz/gal of Optilube XPD (best additive for increasing lubricity to European standards) every time I have fueled the car. The car now has 60000 miles on it and has not shown any signs of cbu. No SES light, still averaging 34 mpg, idle is smooth, and the power is still phenomenal.
> 
> I'm not trying to prove anything here......simply presenting the facts regarding my efforts to supply my 335d with a constant supply of European spec fuel lubricity.


I hope your efforts to feed your d fuel that is as close as possible to euro-spec fuel are successful! I am in a similar position (I have been feeding my d a 5% blend of biodiesel, which is supposed to mimic euro-spec lubricity). Please post back around the 80K mile point.

It seems the CBU statistics are similar to prostate problems in men over 40 (50% in men by age 50, 60% by age 60, and, and, and).

It would be nice to be able to dodge the CBU bullet without having to do radical things like DPF removal.


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## F32Fleet (Jul 14, 2010)

Nadir Point said:


> The injector issue is separate but related to CBU. Diesel injectors die prematurely due to several causes. The biggest problem these days is lower lubricity of commonly available ULSD fuel. Excessive crap coming through the intake causes accelerated fouling after they start leaking from wear. Fuel mileage is the big tell.
> 
> Sent from BimmerApp mobile app


Why do you think it's lubricity and not say inadequate detergents? These cars use a fuel system that has been around for a long time.


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## floydarogers (Oct 11, 2010)

anE934fun said:


> It would be nice to be able to dodge the CBU bullet without having to do radical things like DPF removal.


This is a miss-conception: DPF has little or nothing to do with CBU. It's EGR that is the issue.


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## KeithS (Dec 30, 2001)

At 50K miles I have yet to see an SES light, car runs perfectly. But I think the MPG is down a bit. So either it's nothing, CBU, or a leaking injector(s) which will result in CBU. At least BMW now has a process for cleaning the CBU. But I wonder if they really have a handle on which issue is actually occurring first (which is the chicken, which is the egg).


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## e90Alex (Apr 10, 2014)

anE934fun said:


> I am in a similar position (I have been feeding my d a 5% blend of biodiesel, which is supposed to mimic euro-spec lubricity).


Thanks for this. I was just going to ask if those in states where biodiesel content is mandated have seen a lower or higher incidence of injector problems. I've been loud regarding my dislike of the present of biodiesel in Illinois, but maybe I should embrace it (sometimes).


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## totitan (May 11, 2013)

KeithS said:


> At 50K miles I have yet to see an SES light, car runs perfectly. But I think the MPG is down a bit. So either it's nothing, CBU, or a leaking injector(s) which will result in CBU. At least BMW now has a process for cleaning the CBU. But I wonder if they really have a handle on which issue is actually occurring first (which is the chicken, which is the egg).


I'm not an engineer but it seems apparent to me that the low quality fuel sold in the US is responsible for far more than the well documented HPFP issues in VW products.

I strongly suspect that our substandard fuel causes leaking injectors which in turn create dirty exhaust gasses to be sent through the egr valve, which thereby are a major contributer to cbu. Our engines were designed to run on high quality European fuel. It seems to me that the consequences of not doing so are quite apparent.


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## F32Fleet (Jul 14, 2010)

KeithS said:


> At 50K miles I have yet to see an SES light, car runs perfectly. But I think the MPG is down a bit. So either it's nothing, CBU, or a leaking injector(s) which will result in CBU. At least BMW now has a process for cleaning the CBU. But I wonder if they really have a handle on which issue is actually occurring first (which is the chicken, which is the egg).


CBU is due to a mixture of soot from the EGR and crankcase gases. The million dollar question is what causes the vastly different rates of build up? Some people have CBU under 50k miles, others are over that and haven't had issues yet. Why?


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## DaveN007 (Oct 4, 2013)

anE934fun said:


> It seems the CBU statistics are similar to prostate problems in men over 40 (50% in men by age 50, 60% by age 60, and, and, and).


And allegedly the "fix" to prevent CBU is similar :rofl:

Flog it!

http://www.newscientist.com/article...ect-against-prostate-cancer.html#.U9krmBYpOBI


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## Hoooper (Jun 17, 2013)

I dont see leaky injectors as a significant cause of CBU. With computer controls and the quantity of sensors providing feedback, the fuel would be dialed back if the injectors were leaking enough to affect the AFR, and if they were leaking so bad that the computer couldn't effectively dial it back you would get a code for AFR deviation which would/should be different from the zero adaptation codes that people get. I havent seen anyone report codes that would typically be related to leaky injectors such as cyl x too rich, bank x too rich, etc


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## totitan (May 11, 2013)

Hoooper said:


> I dont see leaky injectors as a significant cause of CBU. With computer controls and the quantity of sensors providing feedback, the fuel would be dialed back if the injectors were leaking enough to affect the AFR, and if they were leaking so bad that the computer couldn't effectively dial it back you would get a code for AFR deviation which would/should be different from the zero adaptation codes that people get. I havent seen anyone report codes that would typically be related to leaky injectors such as cyl x too rich, bank x too rich, etc


Hooper I value your opinion and expertise as much if not more than anyone else on this forum. With all due respect, due you not feel that fuel quality is a contributing factor regarding cbu?


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## Hoooper (Jun 17, 2013)

totitan said:


> Hooper I value your opinion and expertise as much if not more than anyone else on this forum. With all due respect, due you not feel that fuel quality is a contributing factor regarding cbu?


I wouldnt say that. I dont feel its the biggest factor though. Diesels make soot, regardless of fuel quality. The fuel quality can affect the amount of soot produced certainly, and worn injectors can affect the mix quality within the combustion chamber, but I dont see either as the biggest factor. I would love to see a euro 335d EGR log on a stock car and see if it is even close to what the command is for EGR on a US 335d. If it is the same, I dont think there would be much left to blame than fuel quality.

One of the reasons I say I dont see injector leakage as an issue is that we have some people on here at and above 100k miles on original injectors still getting the same mileage they did at 50k (im just getting to 90k myself on original injectors, no additives, and have seen no change in mileage at all). If injector wear was significant enough to be a big cause of these issues at as low at 50k miles I would expect even the most well treated cars to show signs of injector issues by 100k.


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## ingenieur (Dec 26, 2006)

totitan said:


> I'm not an engineer but it seems apparent to me that the low quality fuel sold in the US is responsible for far more than the well documented HPFP issues in VW products.
> 
> I strongly suspect that our substandard fuel causes leaking injectors which in turn create dirty exhaust gasses to be sent through the egr valve, which thereby are a major contributer to cbu. Our engines were designed to run on high quality European fuel. It seems to me that the consequences of not doing so are quite apparent.


The same injectors are not an issue on the E70. Why is that?

California mandates over 50 Cetane and owners there in E90's still are experiencing the carbon as are European markets for certain BMW diesels.


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## anE934fun (May 10, 2008)

ingenieur said:


> The same injectors are not an issue on the E70. Why is that?
> 
> *California mandates over 50 Cetane* and owners there in E90's still are experiencing the carbon as are European markets for certain BMW diesels.


Not quite true. There are variances between refiners that result in some CARB D2 having lower than 50 cetane. I did a test a few years back and found some samples from Valero stations at 40&#8230;.  I passed the test results along to a contact at CARB and the response was that cetane is not mandated by CARB, only the volatility.


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## totitan (May 11, 2013)

While researching this today I found something that may be of interest......carbon residue standards for diesel fuel. I'm out of time now to dig deeper, but I'm curious as to how European and US standards for this compare.


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## tonyspumoni (May 23, 2010)

Sorry to go all academic here, but I pulled this off the web during a search for the term 'fuel lubricity'. Just adding to the concept that indeed fuel composition and microcomposition has a demonstrated basis in types of wear. The paper only reviewed data for gasoline fuels but given the well documented compositional differences between eurospec D2 diesel and US low sulfur diesel, this would make a compelling argument. Also of great interest would be any regional differences in injector failure or CBU, as there are highly likely to be microdifferences in diesel fuels based on regional differences in refining. I have heard that California fuel is slightly different than others and I for one have had two 335ds, both with emissions issues. I think one had an injector failure, but just one injector.

"This paper presents the lubricity measurements of the three commercial gasoline types, unleaded gasoline (95 RON), new super or LRP (96 RON) and super unleaded gasoline (98 RON) and the effects of various physico-chemical properties on lubricity. The results indicate that the nature of the fuel is an important factor for the lubrication properties of each type of gasoline fuel. The potassium content takes an active part in this and the amount that is added to the fuel doesn't seem to affect the final result of CWSD1.4 proportionally. A careful statistical approach to the data identified that, the composition, the sulfur and nitrogen contents, the oxygen content that is mainly contributed from the MTBE content and the viscosity, do affect the lubricity but in a different degree for each type of fuel. This differentiation of the properties' effect on lubricity, reinforces the idea of the complicated wear mechanism that takes place under the specific conditions of the experiments and the important role of the compositional characteristics of the fuel. Oxygen content and MTBE seem to maintain or even increase the wear mechanism. Chlorine was also detected on the metal surface of the specimens after scanning with electron microscopy (SEM)."

From:

Fuel Processing Technology
June 2014, Vol.122:107–119, doi:10.1016/j.fuproc.2014.01.008
Review
Lubricity assessment of gasoline fuels


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## Nadir Point (Dec 6, 2013)

I don't know about all the way down in the weeds chemical analysis stuff, but I do know water is the biggest fuel-related injector nemesis. Commonrail injectors fail very quickly if moisture gets through the system - even emulsified in the fuel at very low doses.


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## Pierre Louis (Oct 23, 2011)

tonyspumoni said:


> ....but given the well documented compositional differences between eurospec D2 diesel and US low sulfur diesel, this would make a compelling argument. Also of great interest would be any regional differences in injector failure or CBU, as there are highly likely to be microdifferences in diesel fuels based on regional differences in refining. I have heard that California fuel is slightly different than others and I for one have had two 335ds, both with emissions issues. I think one had an injector failure, but just one injector.


From the INFINEUM WORLDWIDE WINTER DIESEL FUEL QUALITY SURVEY 2012:

Page 10 gives a graph of lubricity overall and how the trend is.

Pages 127-138 show how the three regions of the US do as far as quality goes.

There is no other published survey of diesel fuel quality comparing different countries that I can find.

Seems to me that both cetane and lubricity are worse in the US, although the lubricity not by much if at all.

The survey is of winterized diesel and may not reflect much better results for "summer" diesel.

The quality of crude oil varies and depends on the source(s), but US production tends to be toward "light sweet crude."

It seems that the quality of North American fuel depends a lot on the additive package. I don't believe that separate regions get the same fuel by any means since each branded fuel has a different additive package and may be from a different source (read: pipeline).

It also seems that finding out which is the "best" cetane improver aftermarket additive should be what we should look for, but of course there are other factors to consider.

PL


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## anE934fun (May 10, 2008)

Out of curiosity, to all who have received the formal diagnosis of CBU…. Have you used any fuel additive (like Stanadyne, PowerService, biodiesel blend, etc.) to improve lubricity of the fuel you feed your d?

I am wondering if perhaps the problem with CBU is related to lubricity of the fuel causing increased wear of the injectors, which in turn leads to higher carbon content of the exhaust stream.


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## Mrguzman (Apr 17, 2017)

Hello all, I have a 2012 x5 35d with 74k miles. Last month the car has been on a down hill. Had the change the egr cooler because a small spring that broke. Had to change the metering valve. And now I have this code 4B73 breather heating stop. I have read endless forums but no one seem to know that this is. Can someone please help me. Car drives fine but just hate the engine light.


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## floydarogers (Oct 11, 2010)

anE934fun said:


> Out of curiosity, to all who have received the formal diagnosis of CBU&#8230;. Have you used any fuel additive (like Stanadyne, PowerService, biodiesel blend, etc.) to improve lubricity of the fuel you feed your d?
> 
> I am wondering if perhaps the problem with CBU is related to lubricity of the fuel causing increased wear of the injectors, which in turn leads to higher carbon content of the exhaust stream.


No. Lubricity (which provides the fuel pump with enough viscosity to keep it from grenading) has nothing to do with CBU. CBU is almost entirely due to EGR in our diesels (or at least that the overwhelming consensus.)


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## floydarogers (Oct 11, 2010)

Mrguzman said:


> Hello all, I have a 2012 x5 35d with 74k miles. Last month the car has been on a down hill. Had the change the egr cooler because a small spring that broke. Had to change the metering valve. And now I have this code 4B73 breather heating stop. I have read endless forums but no one seem to know that this is. Can someone please help me. Car drives fine but just hate the engine light.


Find the pdf file "Advanced Diesel with BluePerformance" (or something like that.) Read p.24; it's the crankcase breather heater that has failed.


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## idiotcentral (May 4, 2017)

I had repeated dash warnings of "service engine soon" on my 2011 335D. They would stay on for two days and go off for a week. Finally got the car to the dealer while the light was on. He replied later that it is throwing seven codes. One for a mass air sensor, and six for rough running cylinders. He said it has carbon buildup on the intakes. That the valve covers have to be removed and the manifold sent to a machine shop to grind the carbon off. Estimated price $2400. And he claims it's not covered under the CPO warranty. Is this correct?


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## Diesel Power (Oct 2, 2010)

To the best of my knowledge, BMW will cover the carbon cleaning. I recommend requesting a meeting with the BMW Technical Support Engineer for your area.


Sent from my iPhone using Bimmerfest


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## idiotcentral (May 4, 2017)

*335 D intake carbon clog*

Thanks. I was essentially given the run-around from BMWUSA customer service. The operator told me it was up to the local service department to determine if the repair was covered under the CPO. I asked for a supervisor to call me back and explain this. She said she would "escalate" the inquiry, though it might take 48 (business) hours for the call back. I called service writer who has the car, again asked for an explanation. An hour later he called back to say that he had done some "digging," and in fact, DIESELS (as opposed to regular BMWs) are covered under CPO for carbon buildup in the intakes. So that's the answer if it happens to any of you.


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## Geotrash (Dec 22, 2013)

idiotcentral said:


> I had repeated dash warnings of "service engine soon" on my 2011 335D. They would stay on for two days and go off for a week. Finally got the car to the dealer while the light was on. He replied later that it is throwing seven codes. One for a mass air sensor, and six for rough running cylinders. He said it has carbon buildup on the intakes. That the valve covers have to be removed and the manifold sent to a machine shop to grind the carbon off. Estimated price $2400. And he claims it's not covered under the CPO warranty. Is this correct?


Nothing needs to be sent to a machine shop any more. There's now a tool and procedure to perform the walnut shell blasting in place, with no mess.


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