# EGR Cooler Replacement



## MotoWPK (Oct 5, 2012)

A few days ago my '14 X5d with just under 49K miles decided to show me its check engine light. Second day at the dealer and the SA advises they have ordered a replacement EGR cooler, expected in tomorrow.

I asked the SA what was wrong with the EGR cooler and he read me some of the tech's notes, which indicated they concluded the EGR cooler was operating a "low efficiency", which I expect would mean it's not cooling sufficiently or not flowing sufficiently.

Now if this is a one time problem resolved by replacing the EGR cooler, that's fine (things happen). Being that warranty ends in about 1000 miles, though, I'm concerned if this is the tip of an emissions control iceberg; e.g. CBU.

What questions should I be asking to try and determine if this is just part of a bigger problem?

(Yes, I did cross post this on bimmerpost in case there are any knowledgeable persons who read this forum but not that one.)


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## n1das (Jul 22, 2013)

"Low efficiency" probably means not flowing well. It's probably getting clogged up due to CBU. The EGR cooler is probably fine and the EGR valve where EGR enters the intake path is getting goooked up due to CBU.

Sounds like CBU developing. What is your driving style like? Do you drive it "gently" or regularly drive it hard and like you stole it? Is the car used mostly for short or long trips?? How does the intake look downstream of the EGR??

It s good that it's being covered under warranty. 

Good luck.

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## ingenieur (Dec 26, 2006)

This was corrected with a software update which would be applied to all X5 diesels. So if that was done at some point and now the cooler efficiency did fault - afterwards you should be good.


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## Nadir Point (Dec 6, 2013)

I don't agree with the "driving style" angle, never have. CBU is a fundamental, systemic problem. It hits diesels harder than gassers due to emissions control designs. It's a question of time + environmental factors like heat, humidity and a multitude of variable related engine-tuning/control inputs.


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## n1das (Jul 22, 2013)

CBU hits diesels LESS hard when they are regularly driven spiritedly like they were stolen and for long periods. Avoid babying the engine by rarely or never getting on the power and avoid using the car exclusively for short trips.

"Drive it like you stole it" applies.

Have fun! 




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## Doug Huffman (Apr 25, 2015)

Consider the EGR contribution to CBU. TDI ALH had a problem with clogging the intake manifold. ~50K miles I had a clean IM installed, and Uwe Ross reduced my TDI's EGR duty cycle to minimum. My TDI had no CBU symptoms when it was sold 130K miles later.

In my neighborhood, my Island, my X5 goes below 2K RPM only transiently, otherwise I drive in MANUAL to keep revs >2K. On start up the engine gets about 30 seconds of gentle throttle getting down the driveway and on down the road a bit to my esses, after the esses it on the throttle to the corner.


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## MotoWPK (Oct 5, 2012)

n1das said:


> "Low efficiency" probably means not flowing well. It's probably getting clogged up due to CBU. The EGR cooler is probably fine and the EGR valve where EGR enters the intake path is getting goooked up due to CBU.
> 
> Sounds like CBU developing. What is your driving style like? Do you drive it "gently" or regularly drive it hard and like you stole it? Is the car used mostly for short or long trips?? How does the intake look downstream of the EGR??
> 
> ...


Hi believe you're correct that "low efficiency" means the high pressure EGR cooler is not flowing well, which would lead to a high temp at its outlet triggering the CEL.

The SA mentioned they'd made a test that sounded like confirming the EGR cooler bypass valve was opening and closing (by applying a vacuum to the bypass valve's actuator). He also indicated they'd confirmed operation of the EGR valve. The cooler bypass valve and EGR valve operation confirmed, I think they've concluded it is the cooler itself and therefor must be replaced. These are based on external tests, however, and no internal, visual examination has been made. When they pull the EGR cooler to replace it, however, examination to confirm if it is CBU fouling can be done.

And, yes, my concern is that the EGR cooler is being fouled by CBU. If that is the case, then I have to wonder what the components downstream of the cooler look like; i.e. the EGR valve, intake manifold and intake ports in the cyl head.

The EGR control software update was done about 15 months ago at ~27K miles. That the EGR cooler would have been clogged by CBU now at ~49K miles (if that is indeed what's happened), gives me concern that the update was ineffective in preventing cooler fouling...or has maybe caused it.


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## n1das (Jul 22, 2013)

What Doug said.

I drive my cars in SPORT mode almost exclusively to keep the RPMs at 2k-ish or a little higher when I'm haulin' ar$e on the highway. I also like SPORT mode in slower moving traffic for tighter control of the car as driving conditions change.


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## Doug Huffman (Apr 25, 2015)

I drive in SPORT/MANUAL except on the freeway about fifty miles away.


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## MotoWPK (Oct 5, 2012)

Expect to have my '14 X5d returned tomorrow with its new EGR cooler. Have discussed with the SA inspecting the old cooler when its removed to see if it is fouled with CBU (which I rather expect) and, if so, the need for a visual inspection to determine if the intake tract downstream of the EGR cooler is suffering from CBU.

In the meantime, I know that BMW has issued SI B 11 03 14, _Diesel Intake Carbon Cleaning_, dated April 2014, which describes what codes are used to determine if CBU exists and how to remove it.

Does anyone know if there is a later SIB on this subject?


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## Doug Huffman (Apr 25, 2015)

*Sooting of intake ports of Diesel engines. Consequences and diagnosis*

https://www.newtis.info/tisv2/a/en/...ir-mass-system/intake-port-sooting/1VnYJPuBIc

Not an SIB and not dated.

*11 12 800. Cleaning cylinder heat intake channels and intake plenum (E70US, M57T2)* The cleaning procedure
https://www.newtis.info/tisv2/a/en/...ls/11-engine/11-61-intake-manifold/1VnXVVS7bq


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## MotoWPK (Oct 5, 2012)

Thanks Doug.


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## jfxogara (Oct 26, 2012)

MotoWPK said:


> Expect to have my '14 X5d returned tomorrow with its new EGR cooler.


EGR coolers break a lot on these cars. While the X5 models are reputed to have less problem with CBU, consider getting tuned and having the EGR assembly blocked. It only costs $80 (the blocking part). There is a "racepipe" replacement for sedans from AARodriguez; you may find there is one for the X5 as well.

As far as driving style, there may be a link to driving aggressively but EGR is clearly a contributor and later models appear to have had some of the problem alleviated. My late 2011 sedan, for instance, had virtually zero CBU at 70K and I do not "drive it like I stole it."


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