Primary & Secondary Fuel filter change question

Executive wrote:
...I always fill my filters before installing,...

That's what I did on my ISL 400. I used a boat fuel filter to filter the fuel prior to putting it in the two spin on filters.

I always pre-fill mine. The one time I did not, I had issues getting it started in spite of following the instructions.

I use Fleetguard filters and they come with the plastic plug for the center hole so easy to pre-fill.

As Don noted, not worth the aggravation of having issues getting the coach started if you install them dry.

it is ok to prefill the primary filter (the first one from the tank)
install the secondary filter dry. the common rail fuel systems have a lot closer clearances in the high pres pump and the injectors and that little bit of dirt that may get into the filter when filling it can cause fuel system issues. also if there are clearance issues getting the filter in position to install it is a good idea to cover the filter with a clean cloth until it is in position to install then remove the cloth being carful not to let any dirt that may have fell on it drop into the filter.

I always fill my filters before installing, it's in my manual. Cummins ISM.....Dennis

You should have a shut off valve so you can shut off fuel to the filters. Turn it off and remove the filters one at a time and replace. Turn on the fuel valve and use the ignition to prime the filters. Do this 6-10 times, do not engage the starter. If it doesn't start, then repeat the 6-10 times prime.

Works for me with a ISC

I had a 400 ISL in a Monaco and changed the filters once a year for ten years and never liked putting them on dry, at least not the primary. The two times I tried, it didn't start. To me, it's not worth the aggravation. I like to put the primary filter on after filling it. Use your thumb or a plug to block the center hole and fill around the outer edges. Install the filter and start the coach. Once you know it's running properly, shut it off and install the secondary filter.

My new coach has a hand primer, so it's a little different.

That's what I do on my '03 400ISL, works for me.