Hello. I am working on a 92 7.3L IDI. I am fairly new to the diesel repair side of the house. Is there anything special I need to know about replacing the fuel water separator filter? Do I need to do anything to take pressure off the fuel system and what is the best method to keep air out of the fuel lines? I saw something about filling the filter up with either diesel fuel or an additive first to help do this but will that actually work?

Thanks

 

If you have the filter with the cup that screws to the bottom, you can upgrade to a less leak prone one like NAPA pn 3417. Fill it with diesel fuel , dieselkleen, or ATF. I reccomend ATF, it will help clean your injectors and pump and is cheaper tha DK. It will probably start, run for a couple seconds, then stall as air makes its way to the inj pump. Don't crank for too long and wait for a minute between cranking to let the starter cool. If it won't restart you may need to bleed it at the injectors. To do that, loosen the lines going to a few of them then crank until you get fuel leaking out.

 

I second bashby's advice to 'upgrade' to a style of filter that doesn't use a 2-piece design like the OEM version. That's one less seal you have to worry about. NAPA 3417 is an option, but here's a rundown of some others:

WIX 33217 is the OE replacement. It accepts the metal bowl from the original setup, so the original Water in Fuel (WIF) sensor doesn't move and therefore should work same as always

WIX 33417 replaces the stock filter with a one-piece design. It has a drain but does NOT have a provision for the sensor. I've been running this one in my truck for the last 2 years with no issue.

WIX 33617 is similar to 33417 but DOES have a provision for the OE WIF sensor, assuming the threads on the OE sensor are 7/16-20

WIX 33805 is the same thing as 33617, but the threads for the sensor are 1/2-20

My understanding is that NAPA filters are re-badged WIX filters. To get the NAPA PN, remove the first '3' (so the NAPA equivalent of 33417 is just 3417).

The system is not under any pressure, but assuming your system is not leaking or allowing air to intrude, the filter will be FULL of fuel when you remove it (like to the brim), so be careful. I had to get creative with an old leather belt to get mine off because it was stuck real well, but otherwise it was pretty straight-forward. I didn't bother filling mine with anything, and it only took a few extra cranks to get her up and running. Filling it with ATF or some sort of additive (or, at minimum, fresh diesel) isn't a bad idea, though.

Mike

 

thanks very much gentlemen for the replies. Great information and I will be able to use that as I move forward. I did look and it already has a NAPA one piece filter on it so the guy I bought the truck from already knew at least part of this information.

 

Use the drain on the bottom of the filter to empty it before you unscrew it. That should keep it from dribbling or dumping all over when you take it off.
Definitely fill the new one (at least most of the way) before you put it on. That will save a bunch of cranking. It also helps to either have the engine warmed up, or the block heater plugged in first to help it start easier.

Also remember to not crank for too long, and let the starter cool off between attempts.

 

with the 33417 does the wif light just stay on? what happens to the sensor?

Dave

 

It never comes on. You just don't plug in the wire.
I've run like this for years.

 

Thanks, thats what i thought , but wierd thing is my WIF light comes on for a while , then goes off, then comes on, it must be the wire grounding out somewhere. i cant even seem to find it. i think the PO might have cut it somewhere.