# Bypass oil filter



## pedser (Jul 19, 2006)

So, want to know if anyone has experimented with a bypass oil filter for their D.

Here's my reason, I used to have a diesel ford F250 and installed an FS2500 bypass oil filter (www.fs2500.com) for over 10 years. One of the things that I liked about it was its ability to filter (clean) the oil on my old truck, in my case it did not matter if it was 100 miles after an oil change or 3000 miles my oil looked the same, clean, NEVER black. I remember having the ability to read the writing on the dipstick thru the oil.

I want to put one in my D but do not know where to attach the in and out hoses out of the oil pump or the block. So, if I can get the diagrams or data I will be installing it and reporting back on how to install and of course showing off my clean oil.


----------



## DnA Diesel (Jul 31, 2010)

Pedser, I had a Cat 2-micron bypass on my Liberty CRD and usually ran 25k per change. I heard nothing but good things about the FS 2500! Problem is, I'm not sure where you would fit an FS 2500 or Cat 2 Mic filter under the 335d's hood.

Cheers
D.


----------



## pedser (Jul 19, 2006)

I agree about the space, I have been looking at the small space betewwn the oil filter canister and the strud wall. One thing is certain, I have been spoiled by the bypass filter ..... because i have not seen black oil like this in a long time.


----------



## F32Fleet (Jul 14, 2010)

Soot loading is a function of the oil. Just because a bypass filter is filtering out more soot doesn't extend motor oil life since TBN continues to be depleted at the normal rate. IJS.


----------



## pedser (Jul 19, 2006)

I Agree with your comment about soot and the function of the oil to includeTBN, but it will be less contaminants providing less friction. ( that is my ultimate goal) 

I am not interested in extended drain intervals, our average 10k / once a year change seems adequate ( specially after seen some other posts with oil testing results and the indication that TBN is at a manageable level after 6k miles) 

Funny .... I have been thinking about doing my own 5000 mile oil change an then letting BMW do the normal once a year change.... ( assuming 10k a year) this may be able to accomplish the same results.

P


----------



## DnA Diesel (Jul 31, 2010)

Equally, TBN is not the only determinant to oil useful life. The composition of the oil overall determines when it's time to change it. While oils are formulate to withstand soot loading, the additional carbon suspended I'm the oil does not positively contribute to the oil's lubricating properties, thus it's removal through the use of a bypass filter certainly will not hurt, and most likely let the base oil and additives get on with doing their job. In fact, I would hazard a guess that reduced soot suspended in the oil would allow low-ash oil formulations that conform to CJ or equivalent specifications to do a better job by reducing the depletion rate of TBN components in the additive package. Of course, by it's very nature, ULSD will result in lower levels of soot anyway, compared to LSD, so a bypass filter may be overkill. In any event, a bypass filter is not going to worsen/shorten oil change periods.

Regards,
D.


----------



## Assimilator1 (Mar 6, 2010)

Tbn?


----------



## DnA Diesel (Jul 31, 2010)

TBN = total base number, originally a reflection of the pH of the oil, which would start out fairly basic/alkaline - usually between pH 10 to 12. Over time, the sulphur and other elements in the fuel that cause acidity would reduce the basic (pH) properties of the oil. As pH was reduced by the effect of the acidic material, the oil's protective properties was degraded. 

More recently, TBN is also taken to include elements of the additive package, even though they don't directly impact the pH of the oil. 

Regards
D


----------



## F32Fleet (Jul 14, 2010)

DnA Diesel said:


> Equally, TBN is not the only determinant to oil useful life. The composition of the oil overall determines when it's time to change it. While oils are formulate to withstand soot loading, the additional carbon suspended I'm the oil does not positively contribute to the oil's lubricating properties, thus it's removal through the use of a bypass filter certainly will not hurt, and most likely let the base oil and additives get on with doing their job. In fact, I would hazard a guess that reduced soot suspended in the oil would allow low-ash oil formulations that conform to CJ or equivalent specifications to do a better job by reducing the depletion rate of TBN components in the additive package. Of course, by it's very nature, ULSD will result in lower levels of soot anyway, compared to LSD, so a bypass filter may be overkill. In any event, a bypass filter is not going to worsen/shorten oil change periods.
> 
> Regards,
> D.


Yep it boils down to a question of $$ vs. benefit. I would be 99% of the people who drive diesels cannot determine "how much" of a benefit they get.


----------



## Assimilator1 (Mar 6, 2010)

DnA Diesel 
Thanks 

(seeing your fuelly sig reminds me mine's disappeared!, gotta find out why....)


----------



## floydarogers (Oct 11, 2010)

pedser said:


> I want to put one in my D but do not know where to attach the in and out hoses out of the oil pump or the block. So, if I can get the diagrams or data I will be installing it and reporting back on how to install and of course showing off my clean oil.


I wanted to mention that the oil system is described in what appears to be great detail in the PDF that Jim posted in the "Everything you wanted to know..." thread. Looks to me like they designed everything right in the block, and that the filter housing doesn't have any fittings at all, and attaches directly to the pump output and block galleries. I don't think it's possible to fit an external filter.

Start looking on P.46 in the "Introduction to diesel technology.pdf" file that Jim posted in: http://www.bimmerfest.com/forums/showthread.php?t=552736


----------



## pedser (Jul 19, 2006)

Yeap, it looks that way. I have been considering changing just the oil filter at 5k after the oil changes to keep the oil as clean as posible specially for 10k (average) change interval in a 335d. 

P


----------



## Assimilator1 (Mar 6, 2010)

Can't see the point in that, yes oil filters will (eventually) get blocked or start to break up (long after their change interval) but they still filter normally during their normal life span, a new filter won't filter any better it'll just last longer.
You might be able to argue changing oil & filter every 5k is worthwhile (although I doubt that really, oils & filters last much longer than they used to, unless someone can link me a chemical analysis showing otherwise) but not just a filter.


----------

