Cat 3126E power loss after fuel filter change

[Troglegs]

I see a lot of comments from folks implying that if you don’t see a second filter under the bed you’ve missed something and I can assure you that is 100% NOT TRUE. I own a 2003 Alfa Leisure SeeYa 38’ Coach with a Cat 3126E and I know for sure my Alfa has ONE SOLITARY fuel filter and water separator single unit in the back by the radiator. On my build my 2002 Freightliner Custom Chassis was delivered to Alfa with ONE filter, supposedly a 2 Micron Filter. I hate this inconsistency caused by Freighliner or Caterpilar… I have friends with C7 Engines and they’ve got the dual filters - yes - two filters, even though one has a fuel water separator, they’re both fuel filters… one is 10 micron and the other only 2 micron. A recent discussion with a fellow Alfa SeeYa owner who originally had only ONE filter on his 3126E supposedly said it can cause premature failures on the HUEI Pump / Injectors… since the 2 micron is restrictive in size…. So he had a shop in Sacramento CA modify his engine to add the second filter and then he added a priming pump and a custom mount for it on the radiator where the original single filter was. I would love to find a true Cat expert who can put this “one versus two - which is better” discussion to bed for good. It’s real frustrating not knowing which micron level filter to use on my coach… and often I have caught mechanics installing the wrong size micron filter on my coach and had to make them change it. Frustrating indeed, seems like there is no standard. Oh well.

[Jay2002]

I've run into this before on fleet trucks with that eng. If we used any filter other than the CAT fuel filter, performance suffered. Good luck

[azlandman]

My 3126 has two filters. One with the water separator which is easily accessible so I can drain the water at every fill up and the other one is on top of the engine toward the front of it which is accessible in my coach under the bed. On my coach that is the one that has a small primer pump. I had a very poorly running engine until I found that other filter and changed it and use the primer pump to fill it. It was a long drawn out ordeal but I have not missed a beat since then.

Originally Posted by Phaeton04

Yes, the engine was running great before I changed the filter.
The filter was last changed last year in November. I prefilled the filter with fuel. I have no Primer handle. I have the 3126E HEP20882 Cat, that has only (1) fuel/water separator filter.
I do not see or smell any fuel leaks.

[wolfe10]

OK, STOP!


Some Freightliner chassis have TWO fuel filters, some have ONLY ONE!

A quick call to Freightliner with your VIN will give you the answers.


Yes, for some chassis model years, the BEAN COUNTERS got involved and decided that only a single filter was needed.

Remember, the engine manufacturer did not spec the NUMBER of fuel filters, only the micron rating that it had to be filtered to.

IMO (yes IMO) if I owned one of the "single fuel filter" chassis, I would add a second one:

Primary fuel filter (between tank and lift pump) a fuel filter/water separator with course element (10-30 micron).

Then after lift pump a 2 micron element (assuming that is the micron rating require for your particular engine/injection system.

[Cat]

Originally Posted by Troglegs

I see a lot of comments from folks implying that if you don’t see a second filter under the bed you’ve missed something and I can assure you that is 100% NOT TRUE. I own a 2003 Alfa Leisure SeeYa 38’ Coach with a Cat 3126E and I know for sure my Alfa has ONE SOLITARY fuel filter and water separator single unit in the back by the radiator. On my build my 2002 Freightliner Custom Chassis was delivered to Alfa with ONE filter, supposedly a 2 Micron Filter. I hate this inconsistency caused by Freighliner or Caterpilar… I have friends with C7 Engines and they’ve got the dual filters - yes - two filters, even though one has a fuel water separator, they’re both fuel filters… one is 10 micron and the other only 2 micron. A recent discussion with a fellow Alfa SeeYa owner who originally had only ONE filter on his 3126E supposedly said it can cause premature failures on the HUEI Pump / Injectors… since the 2 micron is restrictive in size…. So he had a shop in Sacramento CA modify his engine to add the second filter and then he added a priming pump and a custom mount for it on the radiator where the original single filter was. I would love to find a true Cat expert who can put this “one versus two - which is better” discussion to bed for good. It’s real frustrating not knowing which micron level filter to use on my coach… and often I have caught mechanics installing the wrong size micron filter on my coach and had to make them change it. Frustrating indeed, seems like there is no standard. Oh well.

Two filters are better even more so in dusty conditions. Caterpillar found that the filter media for 2 micron could be damaged by larger 20-micro and larger particles. What happens is the larger particles would be collected by the 2 micron filter. But the pressure differential between the fuel coming into the filter/outside of the media and the inside of the media could and did push the larger contaminates through the filter media. So injectors were being wiped out. Also the 2 micron filtered out more so it would plug up sooner- which made the problem of pressure differential on the media worse. Caterpillar did retrofit 20 Micron filters on machines or engines that worked in very dusty conditions.So After learning that all heavy equipment engines have 2 filters. And after Caterpillar went common rail fuel systems they even went to three filters on some/quite a few engines.
So two filters are better but the environment a rv runs in is much cleaner. Want to kill a set of injectors? pre fill the filters incorrectly.

Safe travels