Changing fuel filter Cummins X15..

I’ll tell you how I do it not saying I do it right. I pull that cover off the compucheck fitting I circled in above photo. I have a fitting a 3ft hose and ball valve put together. Hook your hose up and turn key on so electric pump runs. Open your ball valve pointed into catch container of your choice. When the air is out of your hose the filter is bled and she’s ready to run. Remove your bleed hose and reinstall dust cover, with the longer filter I also remove the 8mm bolt and move oil dipstick to make install easier.

 

If you pre fill the engine filter, leave the plastic plug in the center of the filter when pre filling. Remove the plug right before you install. This forces the fuel to flow thru the filter first.

Bugger is heavy tho with a gallon of fuel in it and they arnt the easiest to start.

You can also cycle the key until the return fuel becomes clear of bubbles in the tank. Don’t crank it until all the bubbles are gone.

@wore out has given you the Cummins procedure for removing air from the engine side.

 

Most liekly just a way to prevent contaminants getting into the fuel system... Cummins makes it easy to prime just switching the key on and off 4 or 5 times

 

Do the ISX 15 have the same set up ? I’ve been pre filling my filter then installing it, yes, it can be a ##### to install.

 

One of those fittings as it turns out, is why the blue Peterbilt left me setting 3 times in about 5 miles few weeks ago. Seat wasn’t sealing properly and apparently sucking air in. Didn’t notice it till I bent down looking up under a wiring harness that had it partially covered, seen fuel and air bubbles coming out of the end of it. Mechanic replaced it and it was back to normal….

 

They all have an electric lift pump. Key on and it runs for two minutes. Key off until you hear the modules reset then key on again. 4-5 times should do it. 870, 871 have a plug on top of the gear pump you can loosen to let air purge.