FE10575 vs PF63 (new and old) for L5P Duramax

[TTBadDog]

Long time lurker first time poster. I am looking for a little information on flow rates and such along with GM's change of specified filter for the L5P diesel in the 2500 and 3500 HD trucks. I have included a few links for reference, just trying to be complete. My main concern between the PF63 and FE10575 is are the inlet hole sizes and why GM has changed the filter recommendation. It could just be a commonality or production run thing or the PF63 was changed for another platform and it works just as well for the L5P. At the risk of oversimplifying things, a filter has to have enough goesinta and enough goesouta, filter properly and not bypass.

A little background-
At one point GM recommended and shipped the L5P with the PF-26 filter. Late on GM started to ship the L5P and recommended the PF63, I believe the PF63 has a higher bypass setting. There were 3 part numbers for the PF63, it looks like, among other changes, that the inlet hole size and count changed between each of them and getting larger with the newer ones. GM stated that the change to PF63 recommendation was to improve cold flow performance.
https://gm-techlink.com/?p=16808
Pic of the 2nd and last PN PF63 the one the right is the newest PN.

Not being a fan of the partial plastic construction of the PF63 and some reported gasket issues I went looking for a better filter with correct bypass settings and threads, etc. The FRAM FE10575 is reported to be a very good filter but there is a significant difference in the inlet hole sizes.

The bypass setting for the FE10575 and PF63 are roughly the same at 22 ish. If I go to the FRAM website and enter in the search bar a 22 GMC 2500 6.6 401 cid (that would be the gas engine) the FE10575 comes up as recommended. If I select the 6.6 403 cid (diesel) is does not list the FE10575 filter. If you enter PF63 it will cross to the FE10575 filter.
Result with 401 cid- gas
https://www.fram.com/partFinder/sea...l=0630&engine=V8~6.6L~401~&car-type=car-truck

Result with 403 cid diesel
https://www.fram.com/partFinder/sea...l=0630&engine=V8~6.6L~403~&car-type=car-truck

Result for cross reference the PF63
https://www.fram.com/partFinder/page/index/?q=pf63

So in a nutshell, is there some reason (presumably inlet hole size) that the FE10575 is not a suitable filter for the L5P? Are the inlet holes sizes a critical design spec for a filter when flow rates, cold start and or other factors a big consideration?

 

[BrendanC]

Duramax filters have always traditionally been larger. 10575 is the size for all GM V8’s currently in a suv/truck platform as well as the V6 models.

 

[kschachn]

So in a nutshell, is there some reason (presumably inlet hole size) that the FE10575 is not a suitable filter for the L5P? Are the inlet holes sizes a critical design spec for a filter when flow rates, cold start and or other factors a big consideration?

@ZeeOSix

 

[ZeeOSix]

^^^ The difference in dP vs flow between those base plates is only going to be a few PSI. Really doesn't matter with a PD oil pump. The entire dP across an oil filter is typically only around 1/15th the dP across the oiling system, so the oil filter is a negligible flow restriction to the system.

 

[64bawagon]

Is there any data supporting GM's decision to use this smaller filter on the 2nd gen L5P ? Its just seems small compared to the other generations of Duramax.

 

[ZeeOSix]

Is there any data supporting GM's decision to use this smaller filter on the 2nd gen L5P ? Its just seems small compared to the other generations of Duramax.

Probably a cost cutting filter consolidation move.

 

[64bawagon]

Probably a cost cutting filter consolidation move.

That would be my default for just about anything GM does these days.

 

[ZeeOSix]

That would be my default for just about anything GM does these days.

Production cost cutting is being done by many companies due to the economic environment. Free capitalism at work to maintain profits and stay in business.

 

[Fair enough]

That would be my default for just about anything GM does these days.

They used to make a more slender front pickup still with a full size bed, which would cut material costs. They also didn’t have many things a pickup has now in brakes, safety, mpg, and luxury.

 

[64bawagon]

My question was geared more for the side of the data that proves this new smaller filter is adequate for the L5P application.

 

[64bawagon]

My question was geared more for the side of the data that proves this new smaller filter is adequate for the L5P application.

I have a source with connection to the Duramax people. I am going to try to ask them for some data on how they benchmarked this filter for the L5P application. I keep hearing a lot of talk about people thinking its inadequate for the application but so far I havent seen anything other than anecdotal.

 

[64bawagon]

Here are some pics of the filter that came off my 2025 L5P that I bought May 2025. For reference I added a couple of a Champ XL 10063 that I opened new.

 

[64bawagon]

I put out some feelers for info on the filter in the Dmax application. If I get any info I will post it up.