How to change fuel filter?

Don't know about the ISC 350, but on my M2 with an ISC 330 there are actually a primary and secondary fuel filter mounted near each other. If so, make sure both are changed. There is also an air bleed port on the primary mount of my ISC. Even so, I still pre-fill both leaving the plastic cap/plug in place while filling.

The fleetgard filters come with a little red plastic plug over the threaded hole. Leave the plug in place and prefill. I also prefill with Seafoam to get a little cleaner in the system once a year. Yes, I prefill. I have an electric fuel pump. There is a procedure to turn the key on and off and the system is supposed to pressurize itself. That did not work for me. I was stranded for six hours trying everything I knew to purge the system of air. Nothing worked. Then an old timer from Mississippi told me to cut a scrap of wood, drill a 1/4" hole through the piece of wood, use something as a gasket on one side of the wood, and hold the piece of wood over the tank fill pipe and gently pressurize the system with an air compressor. It only took about 10 psi, then I covered the 1/4" hole with my finger to keep the air from leaking out. I had my wife try and start the engine, and finally, it started.

I realize that many engines do not require the filter to be prefilled. Mine is one of them. However, I see no harm in prefilling no matter what engine you have. I have since changed the filter five more times. I prefilled each time, and have had no issues.

Good luck!

wny_pat wrote:
You are actually suppose to fill the filters from the tiny outside holes around the outer edge, but I have yet figured out how to do that well. But I'm told by the big boys that you go to the hardware store and get a bolt that will screw into the threads of the filter, and then with the bolt in place, you hold the bolt with the filter hanging underneath it and slowly fill the filter thru the outside holes. Do I do it that way? I'm not admitting to noth'ng.

A pipe nipple that screws into the main hole

Ok so talking about fuel filters. I have a 2003 Damon with a 330 cat. How do I change the fuel filter?

Agree, some difference of opinion and also I suspect quite a difference in the fuel system owned by many posters.

It is obvious there are different opinions on whether to fill or not fill the filter before installation. I have watched mine being replaced before and they did not prefill the filter and it started right up, so I won't bother to prefill. Thanks guys for all the advice on the installation method.

brobox wrote:
My 8.3 ISC is self priming, no filling the filter with fuel required. Turn the key on for 30 seconds, two or three time, the electric fuel pump primes it and your ready to go.

ROYBUCK wrote:
The poster was asking about a 8.3 Cummins on my 8.3 you do not fill the filter it is self priming. Roy

Ditto and agreed. The Owners Manual is specific on not prefilling the fuel filters.

HOWEVER, now to add more confusion to the issue....
This past June at the GS Rally in Syracuse, NY, I attended the Spartan Chassis Seminar. The fellow giving the seminar (Mike) from Spartan, also worked for Cummins for several years. When the issue of fuel filter changing came up (and the issue of which filters to or not to prefill) came to front of the discussion, he said that it's fine to prefill the filters if you prefer to do so. Although he did say to prefill via the outer holes, so that the fuel that you are prefilling with is getting filtered

First let me say that I pre-fill my fuel filters before installation.

Second, I have a lift/transfer pump that would supply fuel if I didn't do so.

Third if we don't fill the filter prior to installation where does the entrapped air go when the transfer pump pressurizes the system? I realize there is a bypass loop back to the fuel tank, or the inlet to the injection pump in some cases, for excess fuel to use as a return, but does that eliminate entrapped air if it doesn't return to the tank? If it does return to the tank how long, if ever, does it take for the air to perk out of the fuel? Since there are aftermarket filter systems that claim to eliminate entrapped air from fuel with resulting performance gains it would seem that the fuel is never completely free of entrapped air and that the system as designed is able to cope with that air.

Maybe there are no 100% correct answers to my inane questions, but they are things that make us (me) wonder.

Bottom line, it is a tried and true practice to fill filters prior to installation. I do it with all filters if possible.

Yes, a real problem on many threads like this one is that people give good advice, BUT (big BUT) advice that applies to THEIR rig, not the OP's rig.

This is really worse than no advice at all-- at least then they might consult an authority familiar with THEIR equipment.

As a specific example, the filter change procedure for exactly the same year and model Caterpillar engine is different based on whether the chassis maker installed the Caterpillar manual primer pump (or saved a few bucks by deleting it)! Advice for a non-pump equipped coach based on the procedure used for one with a pump will be DEAD WRONG.

The poster was asking about a 8.3 Cummins on my 8.3 you do not fill the filter it is self priming. Roy