servicing fuel filter 2008 GMC 3500 6.6 deisel...

ord.sgt.26NC

ord.sgt.26NC

Gott mit uns!
Joined
Mar 23, 2005
Location
Goldsboro
time to service the fuel filter on my work truck.I've got a couple of questions.
1- is the spin on filter under the hood the only fuel filter to change?
2-Is this system under constant pressure and if so how is the best way to relieve it without making a mess? Do I find and pull the fuel pump relay to let the engine bleed off the pressure while running?

I'm not versed on deisel trucks so much as I am the heavy equipment we use.
 
Assuming its the same as 01-07 LB7, LLY, and LBZ Duramaxes, there is no lift pump, so there is no pressure, fuel is brought to the CP3 pump by vacuum. There is a petcock drain on the bottom of the fuel filter, but I never use it, after the truck has sat, the filter is usually only half full anyway. Unhook the WIF sensor, unscrew the filter, drain the fuel from the filter, and remove the WIF sensor and install into new filter. I always refill the new filter with fuel (usually I use Power Service fuel additive to fill the filter for a quick clean) to make priming easier. Reinstall the filter, open the bleeder screw, press primer bulb until fuel comes out, with NO bubbles, tighten bleeder screw, and clean up fuel. Press primer bulb a few more times and crank the truck.

Spin on is the only fuel filter to change, unless someone has added an inline filter (great idea).
 
Also, the general way to change the fuel filter is to remove the inner fender to get plenty of room. This makes changing it the easiest, but it is a pain removing/installing the inner fender. I'm not sure if this is still the process for the 07.5+ LMM though, but I assume they left the filter in the same position.

On my 01 LB7 I was able to carefully bend one of the AC lines going to the accumulator about a half inch over(carefully you don't want to kink that line) and it gives enough room to pull the filter up and out of the engine bay without removing the inner fender. Its a little tougher because of lack of space, but makes the filter changes about 30min faster if you can manage.

Also I have seen on ebay where a guy makes these little plastic doors, that you cut a hole through the inner fender in front of the filter, and install the little door there, and all you have to do then is jack the truck up, open the door, and change it out.
 
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