Fuel filters change, ISL 425

[smlranger]

I had the fuel filter change out on my former CAT 3126E down to a science. Now that I have the ISL with two filters, I want to make sure I know the right process in case I need to replace a filter while on the road.

There is no visible primer pump but there is a shut off valve in the fuel line coming into the primary fuel/water separator filter. I figure I need to shut that valve off before removing the filter/s, but do you have to prefill them on the ISL or will it prime them when you crank the engine?

[spike45]

Originally Posted by smlranger

I had the fuel filter change out on my former CAT 3126E down to a science. Now that I have the ISL with two filters, I want to make sure I know the right process in case I need to replace a filter while on the road.

There is no visible primer pump but there is a shut off valve in the fuel line coming into the primary fuel/water separator filter. I figure I need to shut that valve off before removing the filter/s, but do you have to prefill them on the ISL or will it prime them when you crank the engine?

Smlranger,

The Cummins ISL should have an electric priming pump. The O&M manual should say that on a filter change, you operate the key switch by turning on (not sure you need to crank though) for 30 seconds. Do that 3 or 4 times. I am doing this from memory as I do not have one but have read that many others who do rely on the electric priming pump. With Cummins, it not forbidden as in Caterpillar to prefill a fuel filter. Just be certain to fill the outer ring of holes, not the center clean fuel outlet. You may want to go to a hardware store and pick up capplug to insert into the center hole for this purpose. Some recommend using a bottle of auto trans oil to prefill the filter. Consider a bottle of lamp oil as most of that is kerosene with the odor removed. That small amount of kerosene will not be an issue for the injection system.

[tom chelbana]

Gary did a good job of explaining changing fuel filters on dual fuel filters engines. The Cummins presentations also said to fill primary [larger filter] and put the secondary filter on dry.
Tom 04 Essex

[Cat320]

Originally Posted by tom chelbana

...The Cummins presentations also said to fill primary [larger filter] and put the secondary filter on dry...
Tom 04 Essex

My manual says the same thing. Then, after it would not start, I prefilled the secondary and it fired right up.

[becks]

I install mine dry. Mine needs six key cycles before it will start. A friend with same motor only needs four. Do one at a time, start motor and let run a few minutes. Then do the same with second.

[smlranger]

Thanks folks. I'm very skilled at prefilling fuel filters (have the center plug) since that was absolutely necessary on my previous coach with the CAT with no primer pump. I'm at the point where I'm willing to pay the Cummins shop to do my annual stuff but if I need to change while on the road, I just may prefill the filters and be done with it.

[dons2346]

I install both filters dry and it takes 6 turns of the key to fill the filters. I see no reason to pre fill and make a mess.

[Clayobx]

I talked with the tech's at Cummins, 450ISL, they stated simply place on dry, cycle about 30 seconds and fire up! No problems so far.