Diesel fuel filter info

When I changed my own F/W separator, I drained the diesel from the old unit and used that to prime the new one. No air problems. I assumed the fuel would be filtered before entering the engine.

Cummins,, no need to fill fuel filters, the 3 minute run time for the lift pump will do that for you with about 3 cycles.

I would never put transmission oil into the filter for the diesel fuel system. However, on my monaco I would fill the filters at least 3/4 of the way (as high as possible without making a mess) with fresh clean diesel from a can to help the system prime. Only once I could not do that when I had clogged up filters on the road, and it took a good 15-20 minutes for the system to prime both filters and finally run without stalling.

Not all diesel engines have primer capabilities and not adding diesel to the filter will result in a whole lot of air in the system which causes even more issues. If you add the diesel to the outside holes on the filter it will be filtered before getting into the engine - just don't add it down the center hole.

Yep...a great way to ruin your engine. Why would you want to do anything like this?
I don't understand why you would want to carry diesel fuel either...my Ford and GM diesels just need to be either electrically primed or pump primed. You should NEVER add fuel to the filter before putting it on as this puts unfiltered fuel into the engine, and it will explode :)

Yeah, I've heard of all kinds of idiot ideas. Surviving 66 years does that to a fella. Does NOT mean any of 'em is a GOOD idea.

Back in the ancient days, say 1980 and before, those diesel engines would run on anything short of saw dust. Maybe the giant marine engines still have injectors with 1/4 inch orifices like that, but modern diesel engines are picky about their fuel. If you plan to change your fuel filter yourself out on the highway somewhere, perhaps the best course of action would be to put a quart of clean diesel fuel into one of the oil bottles you were gonna throw away after the last change, and keep that in the bay along with the new fuel filter, ready to go. Using a freshly purchased quart of auto transmission fund for the purpose is both more expensive and risky with a newer engine. If anything goes wrong, for sure your warranty will be at risk for having misfueled that engine. And no engine maker's warranty covers misfueling.

I have heard of it, but at $7 a qt, I'll stick with diesel.