Fuel Filter write up

**JPT** · 05-07-2008, 06:33 PM

I had some time today and my truck is about due for a fuel filter so I decided to take pics and do a write up. Here it goes.

Here are the things you will need...
-Fuel filter
-Water in fuel sensor wrench
-Thread tape
-Big oil filter wrench
-Gloves
-Tuperware or cup
-Transgel or other lube for O-rings

I go straight through the top to get to the fuel filter, unplug the WIF sensor connector, loosen the fuel filter with oil filter wrench, then unscrew by hand. I bring the fuel filter up through the AC lines and battery area. Then put the old fuel filter un tupperware.

Next use the WIF sensor wrench and remove the WIF sensor.

Remove old O-ring and give the WIF sensor a shot of brake clean to clean it up, put on new o-ring and a couple layers of thread tape, make sure you wrap the thread tape in the same direction as the threads so it doesnt bunch up while tightening, next lube the o-ring with transgel.

I tighten the WIF sensor snug by hand and then give it a half turn with the wrench.

Then onto the big o-ring, get it set in nice and snug in the groove, then rub some transgel on it, get it in the crack around the o-ring, this will help it stay in during install, next lube the center o-ring/bushing, this will help it slide on nice.

**JPT** · 05-07-2008, 06:41 PM

Then back through the hole and screw the new fuel filter on.

Then snug it up with the big oil filter wrench, not real tight just nice and snug

Then crack the bleeder screw loose and start pumping the primer.

Pump until fuel starts coming out, then snug the screw back up, not real tight you are screwing into aluminum, that why I just use a flat head screwdriver.

Clean around filter with either brake clean or a rag, pump primer a few more times and check for leaks around WIF sensor and top of filter were it meets the housing. If no leaks, start truck up and check for leaks while running. If no leaks, then you are done and just saved yourself lots of easy money. Do this every 10-15K miles, it only takes about 10 mins and is very easy. Hope this helps some people out and encourages them to try it themselves.

08lmm/white · 05-07-2008, 09:36 PM

Very nice pictures and write up!! Is this on a new LMM motor??? Mine looks so tight to get at, but if you can do it, I'll give it a try next time as going through the wheel well is a pain in the @ss.

psyco66 · 05-07-2008, 09:53 PM

I have been a diesel machanic for 10 years. I feel you should not lube the o rings with grease. You should lube any o ring with what it is going to live in. For the fuel filter just put a little diesel on it and that is it. The grease is not a good idea. JIMO.

**JPT** · 05-07-2008, 10:13 PM

Quote:

Originally Posted by psyco66

I have been a diesel machanic for 10 years. I feel you should not lube the o rings with grease. You should lube any o ring with what it is going to live in. For the fuel filter just put a little diesel on it and that is it. The grease is not a good idea. JIMO.

I am a GM diesel tech at a dealership, thats how I was taught and how I've been doing it on my duramax and customers for years, never had an issue or come back because of it, but everyone has their own opinion.

**JPT** · 05-07-2008, 10:15 PM

Quote:

Originally Posted by 08lmm/white

Very nice pictures and write up!! Is this on a new LMM motor??? Mine looks so tight to get at, but if you can do it, I'll give it a try next time as going through the wheel well is a pain in the @ss.

This is on my LB7 truck. The newer ones are a little tougher but I still do it the same way, the California emissions trucks are more of a PITA too.

dmax500 · 05-07-2008, 11:03 PM

the new lmm trucks unless you have some very small arms you have to take out the fenderwell to change the fuel filter. just to give you an idea warranty time on a 07 classic to change the filter is .4 hrs the new lmm is.7 almost double the time. time out of mitchell is .8 for 06 there is no times yet for the lmm's but going off warranty time most likely 1.5 for customer pay.

dmax500 · 05-07-2008, 11:05 PM

also about the o- rings imo spray em down with wd-40 works great and will still fire if run through injectors.

psyco66 · 05-07-2008, 11:14 PM

That is why I do not like the grease. It will not pass throught the injectors. That is why I say just put a little diesel on them. But that is JMO.

**JPT** · 05-08-2008, 12:13 AM

Quote:

Originally Posted by dmax500

the new lmm trucks unless you have some very small arms you have to take out the fenderwell to change the fuel filter. just to give you an idea warranty time on a 07 classic to change the filter is .4 hrs the new lmm is.7 almost double the time. time out of mitchell is .8 for 06 there is no times yet for the lmm's but going off warranty time most likely 1.5 for customer pay.

Fuel filters wouldnt be replaced under warranty unless there was a problem from the factory, I have never replaced a fuel filter under warranty, that is like an oil change being done under warranty, anyways, this is just a write up of how I do them, you can change some things or do it how you want to, this is just some simple direction for those who have not done it. Sorry its not to your guys standards

And yes the LMMs are more of a bitch with everything, like changing the belt

, they pushed the firewall forward and everything is alot more cluttered.