Questions on Aftermarket Diesel Truck Fuel Filter System Options

All,

Hi - new to diesels. Purchased a 2017 F350 SD Crew Cab LB Diesel. Before buying this truck, it became apparent that all the new diesels get significant attention regarding protection of the fuel rail and injectors. So, I want to spend some money now as insurance to hopefully avoid the problem and not have to spend a L-O-T later.

That gets me to being new to diesels, and asking for recommendations on brands of fuel filtration systems here. I’m very familiar with FASS, and I also see Air Dog. My wife and I watch a lot of rig reviews on YT and most of the serious rigs the owners/builders rattle off the mods and there is inevitably a fuel system mod, and FASS is the name I hear alot. So I’m focused on them, they seem to have a solid reputation.

Does anyone have any brand that nudges FASS to the side? I appreciate any information, as i really want to protect our investment. NOTE: The truck is BONE stock, and the engine will remain that way, no power adders, no tune. My goal is reliability.

Thank you,
Barry
 

Joe917

Explorer
On our Mercedes OM366 in addition to the factory filtration we added a Parker Racor 10 micron with water separator. After a day on the "Trampolin del Diablo" in Colombia which seriously shook up our fuel tank we blocked 3 filters in 3 days. Unable to source any more new Racor filters that size we switched to a larger Mann water separator filter. The Mann filter housing failed in Bolivia (the priming pump started to let air into the lines). The replacement Mann filter system has been fine.
The key thing for an additional filter is to have a water separator as part of the filter. A pre filter with high flow capacity will extend the life of the factory filter. When you add to the fuel system you are introducing new possible points of failure, just be aware.
 

Alloy

Well-known member
On custom fuel systems I don't follow the idea of having a clean outs at the bottom of diesel tanks. Only time they get used is when there is a problem. It is better to have everything collect at a low point so it can be drawn out into a sediment / water separator with a huge clear bowl + an (diesel only) alarm.

I've seen many fuel/water separators that it is impossible to see they are full of water due to the bowl being too small and/or off color (yellow/bronze/blue).

This is what we use to use
1623097138523.png


Once the fuel has gone through the sediment/ water separator then I'd have dual filters.
1623096403878.png
I'd also have a pump so fuel can be filtered from tank to tank.

Keeping the tanks full reduces condensation.
 
On our Mercedes OM366 in addition to the factory filtration we added a Parker Racor 10 micron with water separator. After a day on the "Trampolin del Diablo" in Colombia which seriously shook up our fuel tank we blocked 3 filters in 3 days. Unable to source any more new Racor filters that size we switched to a larger Mann water separator filter. The Mann filter housing failed in Bolivia (the priming pump started to let air into the lines). The replacement Mann filter system has been fine.
The key thing for an additional filter is to have a water separator as part of the filter. A pre filter with high flow capacity will extend the life of the factory filter. When you add to the fuel system you are introducing new possible points of failure, just be aware.
FASS and AirDog both have a water separator as part of the system
 

twodollars

Active member
On your truck, factory filtration is not the weak link, the cp4 high pressure pump is. I would focus on using a publicity additive, something like howes, and try to prevent that pump from failing. When they fail they tend to fill the fuel rail and injectors with debris, making the repair very expensive. Just my experience on a fleet of 30 diesels.
 
On your truck, factory filtration is not the weak link, the cp4 high pressure pump is. I would focus on using a publicity additive, something like howes, and try to prevent that pump from failing. When they fail they tend to fill the fuel rail and injectors with debris, making the repair very expensive. Just my experience on a fleet of 30 diesels.
Thank you everyone for all the replies. The above is exactly what I’m concerned about.

That said, I don’t have hard data on how often the CP4 fails. It is used in many models/brands, so logic would dictate it can’t suck that bad, right? I’m trying to avoid overzealousness and curing a problem that may exist, with an ounce of prevention.

So the more I’m reading (and getting responses like in this thread) I’m hearing “factory filtration is good, change filters more often than manuf recommendations, keep a 1/4 tank in at all times, and run a high quality diesl additive that reduces friction”.
 

twodollars

Active member
Personally I think your on the right track. The cp4 is in hundreds of thousands of engines, and in most never comes apart. Still, I'd use a lubrication additive, and chances are you'll be fine. I saw about 7 percent failure rate on our d max trucks. They towed every day, and seemed to fail the pump at about 150k if it happened.
 

Darwin

Explorer
You might look into that "disaster" set up that re routes the fuel in case the CP4 starts throwing metal. It will save your fuel system and injectors etc. basically a $12000 repair.

Ram went to a Cp4 in 2019 and 2020. In 2021 they went back to a Cp3.
 

Wilbah

Adventurer
I know very little about diesel issues with fuel systems but two dollars comments jive with other things I've read. This is an article abt boat engines but discusses the same points re lubricity of the fuel and definitely appears to me to be one of those "ounce of prevention" type things.

Also just FYI I saw materials Amsoil has on their diesel additive for this issue and if their materials are accurate for the other mfr they listed in their testing, their additive rate (640:1) was far less than the others (200:1 etc) so I would look at the net total cost of an additive. An extra $1 per bottle may be cheap money if it treats 3x the fuel. I did also see they have 5 gallon buckets (and other sizes) that are about half the price of the 8 ounce bottles (per ounce), so some planning/calcs for your fuel needs makes sense.

 
Yup - I think I’m in the “I have a warranty” and “I’ll add a quality fuel additive” and call it good. Thanks everyone. I had a local shop doing a hard sell that I thought was good advice. I got wise.

I appreciate everyone’s input.
 
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