is it hard to change the fuel/water filter?

Ivylog,

Agree. That is exactly how I change the filter on 2003 Cummins ISL. Install filter dry, turn key. Cycle a couple of times. Start and drive off.

One of the other issues is how high the filter head is located relative to level of fuel in the tank. If the filter head is higher, when the filter is removed, the fuel will drain back to the tank, leaving you with 30+ feet of AIR in the fuel line. Best answer is to install a ball valve on the fuel inlet to your primary fuel filter.

I answered the OP's question who has a 2002 ISC Cummins 8.3L engine with a 12V lift pump that runs for aprox 30 seconds after the key is turned on...same as a ISL. In 13 years and 80K miles I have never prefilled my fuel filters on my ISL...The Only engine I do not prefill the filters making it easy to change on the side of the road.

You MUST prefill the filters on a Cat engine and even then you will probably have problems unless you've added a hand priming pump. Cat engines do not use electric fuel pumps.

The procedure for changing filters completely depends on what engine and fuel system you have.

What works well with one does NOT mean it will work with other systems.

Each of our three diesel coaches had a different procedure for filter change/priming. Not better or worse, just different. PLEASE read your manual.

I've been changing my own filters for over 13 years on two different DP's. As stated, the hardest part is getting to it (on some coaches) and breaking the old one loose, especially if a gorilla put the last one on.

Inspect your new filter to see how many seals it has. Typically, as stated, there is a seal built into the lip of the filter and a second one that seals the center nipple on the filter mount. On your filter, the fuel flows into the outer holes and is drawn up through the large hole in the center. That center hole is threaded and screws onto the nipple on the filter mount. Since that nipple is where the fuel is sucked up and out of the filter, it needs an o-ring to seal it from the incoming fuel. Many will forget to remove that old o-ring, which usually stays on the nipple, and will later have issues drawing air.

I will disagree with not filling the filter. There is a procedure for cycling your gnition on and off, but it can be a nightmare. It is so much EASIER to pre fill the filter. The concern is that the fuel you add will be unfiltered. I simply plug the center hole with thumb (make sure it's clean) or you can use a piece of threaded pvc and just fill the filter via the outer holes.

My Diplomat had two fuel filters side by side. The water separator and secondary filter. I always replaced the main filter (pre filled), fired up the coach and let it idle for a minute or or two. Then I would remove the second filter and do the same thing.

Side Note: If you look, there are kits out there to relocate fuel filters that are hard to reach. To me, this is a no brainer. If you have filter issues on the road, I would certainly want the filter to be easy to reach.

Don't forget to buy a second filter and keep as a spare. Use it next time you change filters and replace with another new spare.

We need more information to be able to give sage advice:

Do you have one or two fuel filters? If one, is it on the suction side or pressure side of the lift pump. Said another way, is it between the tank and lift pump or between the lift pump and engine?

Ball valve/shut off valve on primary/only fuel filter?

Is the primary/only fuel filter above or below the level of fuel in the tank?

I'd take the old one off (probably the hardest part), check that both rubber gaskets came off...the small one on the threaded nipple often stays on. Put a little oil on the outer gasket, put the small one on the nipple and put the filter on dry...no fuel and hand tighten. Turn the key on for 30 seconds, four times and then start the engine. Your lift pump, which cuts off after 30 seconds, will fill the filter in the two minutes it runs while you cycle the key four times.

If you change both filters you need to cycle the key 6-8 times and check for a fuel leak on the secondary filter with the engine running.