# Diesel fuel filter



## KeithS (Dec 30, 2001)

Correct that if your toe is in/out the car will not pull, will only wear tires. I check my tire wear when I check tire pressures. Actually for a BMW there is more alignment to be done in the rear than the front. I'm pretty good at feeling when a tire is out of balance so only get it when needed. I've even run into the problem where the tire may be balanced, but I still feel a vibration due to load force variation in the tire (tire construction).


----------



## BB_cuda (Nov 8, 2011)

My car has been driven carefully always going slow over bad spots and avoiding pot holes so far. I have equal pressure in both front tires and no pull. I got the one guys point about toe in/out. Car has too few miles to need this. Now, i did call Benson's, great front end shop in Clear Lake, Texas. They said they can align BMWs for $69. I will get new tires in another 6 -8k miles and go to Benson's.

One more thing, when i got the oil change yesterday, they lost the little door that covers the drain plug area of the engine. I called this morning and they ordered me a new one that i will have to go pick up on Tuesday. I just don't want to drive back to downtown. I did buy an extra quart of oil while waiting for service and the parts guy gave me one of those black oil pouches with the zipper for free.


----------



## F32Fleet (Jul 14, 2010)

Just had alignemnt for $89. Picked up some REO 960AS RFT as a replacment for my conti's. I run 32/35 psi


----------



## kozlio (Mar 14, 2018)

BB_cuda said:


> @snipe: I have conflicting information on the interval. This document [attachment] says every 2nd oil change (marked page 9, pdf page 13). I found it on a thread discussing the above somewhere.
> 
> My service book named "Service and Warranty Information: 2011 1 series, 3 series, 5 series and Z4" says every 3rd oil change. In my book, it is on page 12.
> 
> So, my car is up for its 2nd oil change. I scheduled an appt and called SA to ask which is it. She looked it up and says 3rd oil change.


BB_cuda, is there a need to prime the ff and the line on a x5d vs. 335? I see your contributions on the other diesel forum re: 335d
https://www.e90post.com/forums/showthread.php?t=799059&highlight=Fuel+filter&page=11
Was wondering if the design on my x5d builds on experience from older 335d... I suppose for a peace of mind re: hpfp, i should go ahead and software-trigger the lift pump to prime the diesel lines


----------



## Doug Huffman (Apr 25, 2015)

kozlio said:


> I suppose for a peace of mind re: hpfp, i should go ahead and software-trigger the lift pump to prime the diesel lines


"Before starting the engine, switch the ignition on and off several times until the electric fuel pump fills the fuel system."
https://www.newtis.info/tisv2/a/en/...enance-general-note/00-00-maintenance/HKK3BE0


----------



## alacey (Mar 14, 2018)

Speaking of diesel fuel filters. My next oil change will be my fourth PM since my fuel filter was last changed by the dealership. I am probably going to change it myself. Any tips or tricks I may need to know?


----------



## jfxogara (Oct 26, 2012)

alacey said:


> Speaking of diesel fuel filters. My next oil change will be my fourth PM since my fuel filter was last changed by the dealership. I am probably going to change it myself. Any tips or tricks I may need to know?


Yes.

https://www.e90post.com/forums/showthread.php?t=799059


----------



## kozlio (Mar 14, 2018)

For those who took the time to read the 335d ff thread in posts #24 and #27, it boils down to 3 methods to finish the ff replacement process: 1) start electrical (without ignition) as in post #25 above and wait for 60 s to prime lift pump, 2) use a scan tool or ediabas to software-trigger the lift pump to purge the air/prime pump, and 3) manually tigger the pump from under the rear seat. So those were the options for 335d which I suspect is quite similar for our D’s (x5d, 28d).

Re: option 1) (instruction in post #25) in that thread for 335d, users are reporting that didn’t work for some, while others are advising against any potential subsequent dry-cranking to engine start.

My question was around the difference with x5d - does the 60-sec electrical power on in post #25 actually work before I get myself stranded in the driveway without any transportation to work 

Is this the true and tested way to prime the fuel pump for x5d? (if I recall correctly from my golf tdi days, the excessive cranking wasn’t sounding too healthy and that’s what I wanna avoid.)

Thanks very much


----------



## Doug Huffman (Apr 25, 2015)

I serviced my TDI for thirteen years. I changed the fuel filter with every oil change. I pre-filled the fuel filter and started the motor. It may have taken three more seconds to catch and ran rough for another few seconds, but for thirteen years.


----------



## robnitro (Aug 3, 2016)

Doug Huffman said:


> I serviced my TDI for thirteen years. I changed the fuel filter with every oil change. I pre-filled the fuel filter and started the motor. It may have taken three more seconds to catch and ran rough for another few seconds, but for thirteen years.


Why every oil change? Was it to make you feel better? At the low fuel rate the tdi uses, those filters are good for 30k minimum!
Filters get more efficient with use. A new filter is least efficient.
Best investment was a filter minder for my air filter and a 2micron filter for my TDI, both of which are on my 35d now. 
What's funny is that the 2 micron filter rated by fuel gallons translates to 3+years on the 35d. 
Oh and the air filter mythos applies too, the restriction gauge shows at most 2 in h2o on a 2 year old filter. I changed it because it could have been more than 2 years old from the previous owner.

Of course in some cases of smaller air filters, a year is good, like on the 335d. But for fuel, 20k/2 years minimum is fine.


----------



## kozlio (Mar 14, 2018)

robnitro said:


> Why every oil change? Was it to make you feel better? At the low fuel rate the tdi uses, those filters are good for 30k minimum!
> Filters get more efficient with use. A new filter is least efficient.
> Best investment was a filter minder for my air filter and a 2micron filter for my TDI, both of which are on my 35d now.
> What's funny is that the 2 micron filter rated by fuel gallons translates to 3+years on the 35d.
> ...


Ff should be replaced every 2nd oil change, apparently. I'm def overdue and will tackle this by year end. Ive already put 35k hwy kms on my x5d since i bought it last winter.

Rob, re: secondary fuel filter, the 2 micron, ur refering to, this is from here, right?

https://www.e90post.com/forums/showthread.php?t=776965&page=2

I hope i don't get banned crosslinking useful info from another bmw forum. I'm also interested in doing that. Is the wik filter module u used? What plumbing adjustments u had to do.


----------



## Doug Huffman (Apr 25, 2015)

robnitro said:


> Why every oil change? Was it to make you feel better? At the low fuel rate the tdi uses, those filters are good for 30k minimum!
> Filters get more efficient with use. A new filter is least efficient.
> Best investment was a filter minder for my air filter and a 2micron filter for my TDI, both of which are on my 35d now.
> What's funny is that the 2 micron filter rated by fuel gallons translates to 3+years on the 35d.
> ...


3,000 mile OCI but full interval on a filter.

In my career I depended on breathing air filters in atmospheres potentially immediately hazardous to life and health, and which had no indication of exhaustion. *The thought that a filter becomes more efficient with use is ignorant in the extreme.*


----------



## alacey (Mar 14, 2018)

Actually, that is not the first time I have heard that some filters can actually increase their efficiency(the amount of contaminants they trap and/or let through) with use. I have heard this from representatives from all of my companies major filter suppliers (Racor/Baldwin, Donaldson, and Fleetguard) on multiple occasions. 

From what I was told, the filter will trap the contaminants in the media which will eventually stack on top of each other over time trapping even smaller particles. The problem arises when it becomes too efficient at trapping contaminants(clogged) that it does not allow enough fuel to pass.


----------



## Doug Huffman (Apr 25, 2015)

What is the purpose of a filter, to pass in specification fluid or to block out of specification stuff?


----------



## alacey (Mar 14, 2018)

Doug Huffman said:


> What is the purpose of a filter, to pass in specification fluid or to block out of specification stuff?


It depends on the filter and what it is being used for, but most are meant block out a specific size and amount of contaminants. When they cannot pass a specific amount of fluid or air, then they need to be changed because they have reached their holding capacity. A filters efficiency rating is different than what most people think it is. Most people think that it is the amount of fluid(or air) it can flow, but that is false.

A filters efficiency is the amount of contaminants does not allow to pass, not the amount of fluid it can pass. The efficiency changes depending on the size of contaminants. For example, 3 micron filter with a 95% efficiency can trap 95% of all contaminants that are 3 microns and 5% will pass through. That same filter may have a 97.5% efficiency of trapping contaminants 5 microns and 100% efficiency of trapping contaminants 10 microns or larger. As time goes on, the filter traps more contaminants which will generally increase its efficiency at certain microns, but will decrease flow.

However, some filter manufacturers started adopting the beta ratio method(particles up stream/particles downstream=beta ratio) as a means to rate their new ultra high efficiency synthetic filter media since two filters efficiencies may be small percentage wise, but their beta ratio will be much larger which helps differentiate the two. For example, a filter with a 99.5% efficiency will have a beta ratio of 200(5,000 particles allowed to pass) while the 99.9% filter will have a beta ratio of 1,000(1,000 particles allowed to pass).


----------



## alacey (Mar 14, 2018)

I will also add that knowing a filters micron rating is just about worthless without knowing it's efficiency at said micron. You can have three different filters that are advertised to have a 3 micron rating. However, filter one may have a 90% efficiency(trap 90%/pass 10%), the second may have a 95% efficiency, and the third may have a 99% efficiency for 3 micron particles.


----------



## n00bkiller944 (May 21, 2018)

TDIwyse said:


> Since the HPFP is lubricated by fuel it's very important to properly bleed the fuel system after changing the filter. There's a couple ways (that I know of, but might be more) you can accomplish priming the system by activating the low pressure fuel pump to push fuel through the system. One is to use the Bavarian Tech tool to initiate the low pressure pump. The other that tlak77 told me about was to use the "start/stop" button, but NOT starting the car (key in, do not press on the brake pedal, and then hit the button). Might take several iterations of either step to pump enough fuel.
> 
> When I change fuel filters in my diesels I prefer to flush the filter (~gallon of fuel) before hooking the clean side of the filter back into the system in case there's any contaminates on the clean side from manufacturing/shipping/storage. After connecting the clean side then finish priming the system before starting the engine.


How do you flush it. Using the method of pressing start stop button to cycle fuel through the filter disconnected?


----------



## Michael47 (May 9, 2014)

For what it's worth, as far as I can tell, with all service being done by either dealers or reputable indy wrenches, my 2012 X5 35d fuel filter was never changed until at 106,000 miles, it sprang a leak. That none of those dealer or indy SAs ever suggested a fuel filter is, um, IMPRESSIVE to say the least. In any case, the filter got changed at a dealer who discovered the leak when replacing the DEF tanks under warranty due to an issue. BTW, that warranty replacement was (surprise to me) covered, even though it was only a week later that I got a notice from BMW extending that warranty to 156K miles.

Also, for what it's worth, what's up with BMW sticking the filter in such an inaccessible position? I've never owned a vehicle with a fuel filter that hard to replace in the half century I've been responsible for auto maintenance. Everything else has had the fuel filter right up front where it practically shouted at you to change the thing from time to time.


----------



## Michael47 (May 9, 2014)

Doug Huffman said:


> *The thought that a filter becomes more efficient with use is ignorant in the extreme.*


I beg to differ with you, Doug. The truth is that filter effectiveness changes throughout the life of the filter. Initially, it is whatever it was designed to be, but as filtrate begins to build up, the pores start to clog up, become smaller, and the filter becomes more effective. Eventually the pores fill up so much that the filter no longer flows "enough" (whatever that means in the application at hand), and the filter is officially clogged. The trick, of course, is to replace it before it reaches the "clogged" status.


----------



## kozlio (Mar 14, 2018)

Michael47 said:


> I beg to differ with you, Doug. The truth is that filter effectiveness changes throughout the life of the filter. Initially, it is whatever it was designed to be, but as filtrate begins to build up, the pores start to clog up, become smaller, and the filter becomes more effective. Eventually the pores fill up so much that the filter no longer flows "enough" (whatever that means in the application at hand), and the filter is officially clogged. The trick, of course, is to replace it before it reaches the "clogged" status.


By that logic, i should not change my brita water filter either


----------

