PMCS Check Question: Fuel Filter

[todds112]

I am confused on this one thing. Do you open the water drain valve on the bottom of the filter with the truck running or not? I have tried the big one with it running and nothing really came out. I tried it with the truck off and I could hear air bubbling up into the filter Again, only a dribble of liquid came out what seemed to be clean diesel. I had to prime the truck to get it running again. I think maybe the drain valve is crudded up too. I'm gonna change out all the filters here ASAP.

 

[todds112]

Now I'm confusing myself reading the TM. It seems to infer the 939A2 doesn't have the big filter under the fender, but clearly I do. Do you drain both filters regularly or just the smaller one on the side of engine?

 

[Artisan]

Field Maint manual 2 PDF pg 834 right?

I do not see anything that says START ENGINE.

Open petcock and drain off any water, probably matters not if running or not.
Safer not running.

Remove the whole shootin match to replace filter.

Fill w/ fuel BEFORE you re-attach things and you will prob not have to prime.

 

[98G]

Now I'm confusing myself reading the TM. It seems to infer the 939A2 doesn't have the big filter under the fender, but clearly I do. Do you drain both filters regularly or just the smaller one on the side of engine?

Some A2s have the big one on the firewall and also the small one on the block, and some just have the small one on the block.

A word of caution - filling the filter with fuel to avoid priming results in the introduction of unfiltered fuel into the injectors. The cummins manual for my ram specifically advises again this.

 

[crolfe1984]

My truck only had the small driver's side filter.

Per the TM, and I've done this to my M923A2, you should replace the fuel filter and prime by loosening the 10mm bleed bolt on the far side of the IP (injector pump). Then press the button on the lift pump until a trickle of fuel leaks out. Tighten the 10mm bolt back down and fire it up. It took about 60-70 pumps for me to get fuel up there and I had zero issues getting it started.

 

[todds112]

Could I just do away with the larger filter and assembly? Be one less failure point (and maintenance item).

 

[MtnSnow]

Yes you can but I will also mention that you will most likely need to replace the block mounted filter a bit more regularly since it will plug more easily than the large canister. What I personally would suggest is doing away with the canister filter and install in it's place a spin-on filter system which will allow for better filtering as well as simplicity of filter changes going forward

 

[Floridianson]

I have switched to spin on oil filter and spin on fuel filters and for the amount I have driven I found it cheaper to leave the canisters alone and just change the filters when I get the truck. They will out last me. I don't think there is anything wrong with our fuel filter system just priming it up for the first time after filter change. Save the money and buy the better half some flowers.

 

[98G]

Could I just do away with the larger filter and assembly? Be one less failure point (and maintenance item).

More filtration is better. I would not opt to remove the large canister filter. Many people add additional filtration as an aftermarket upgrade to diesel engines.

The small filter on the block is prone to clog. It is worth carrying an extra one with you. The large filter on the firewall has much more surface area than the small one and is less prone to clog. My idea of a near optimal solution is to run a coarser (10-20micron) filter media in the firewall filter as a prefilter and water seperator, then run a finer filter (5micron, or perhaps even 2-3micron)on the block to provide the engine with the cleanest fuel possible.

My current A2 only has the small filter on the block. I'll be adding additional filtration upstream, either a stock firewall filter or a spin on in the stock location.

 

[todds112]

That all makes sense, thanks for the input.