WE ALSO REBUILD THE FUEL FILTER HOUSING
WITH A LIFETIME WARRANTY
Fuel Filter replacement remove and install Instructions
Read these Instructions completely noting the needed step stool or ladder for your needs. Further, study pictures of
this project before starting for safety and success.
These instructions require the Dmaxwrenchkit #1088 the only wrench kit designed specifically for this application at
This remove and Install wrench (right side in picture above) is sized to fit in the small area where the filter is located on
the passenger side of the engine bay.
Please be careful to make small precise movements with the wrench as it fits precisely around the filter. The handle is
made to work in the engine bay's limited space.
ENGINE SHOULD BE COLD NOT RUN IN LESS THAN 3 HOURS AS A HOT ENGINES
CONTAINS HOT PARTS!
Find the fuel filter on the passenger side of the engine toward the firewall, on the filter head mounted to the engine.
First, disconnect the water sensor wire connector by running your left hand carefully along the bottom of the fuel filter,
grasping in your fingers the wire of the water sensor.
Note the connector in this photo.
Find the Wire keeper and peel it back as it holds the wire to the valve cover.
Finding the connector along the wire, then finding the compressible tabs on it, squeezing the tabs you will feel, and
pulling using your fingers, this will take a bit of effort the first time. You may want to look down at the bottom of the fuel
filter with a flashlight before you do this.
Grasp the Dmaxwrenchkit's Remove and Install wrench with the jaws in a horizontal position and position it at the upper
portion near the seam (for 2001-2004.5 Duramax Diesel)
(2004.5 -20011 Duramax Diesels need to be gripped at the middle or toward the bottom of the filter),
then, depending on which way you first position the wrench flip it over, if needed, and pinch the handles together
farthest away from the direction you want to turn the filter, and gripping firmly, quickly move the wrench. It will move a
small amount. Repeat this a number of times till it is loose or tight enough for your liking.
Then remove the wrench after you have broken the threads initial tightness ( this may be hard at first but a firm quick
movement of a firmly grasped wrench in short strokes will break it loose).
Loosen the filter the rest of the threaded distance with your hand only and then let it hang on the nipple of the filter
head as it will hang safely there or you may go to the next step.
You may need a step stool or ladder now to perform this task depending on arm length and your overall height.
Then slowly lower the filter with the water sensor attached to the frame rail and set the filter carefully upright.
Then go inside the wheel well and pull the lower plastic wheel well cover back with the left hand and use the other to
grasp the filter sitting upright on the frame rail.
Now drain the filter either by putting the threaded head side of the filter down in a container or using the Kit's water
sensor wrench and the Remove and Install wrench holding the body of the filter to loosen the water sensor and
unscrewing it over a container to catch the fuel.
Remove the old o-ring from the water sensor and put the new o-ring from the new filter box on the water sensor. Then
put the water sensor in the new fuel filter bottom and tighten 1 turn past o-ring contact and then 1 full turn more. You
may tighten it more you if are comfortable as the water sensor wrench will allow you to remove the sensor with no
problem the next time you replace the filter.
Now take the filter with the sensor attached as above and go to the wheel well and with your chest on the tire peel the
lower edge of the plastic back and set the filter upright on the frame rail.
Next looking down into the engine bay with your left hand grab the filter and bring it up. You may need something to
stand on to grasp the filter on the frame rail.
Then take the new o-ring from the new filter box and set it with your right hand in the groove on the edge of the new
filter as you observed it on the old filter.
Raise the filter toward the filter head and notice the rubber center on the filter is designed to be friction fit on the nipple
of the filter head, When fitting the rubber center to the nipple, it will take a bit of effort the first time but you will
accomplish it, push up firmly with out threading it yet. It will safely hang on the nipple and you may remove your hand
Now remove your hand and rest a bit as the next step requires a rested hand.
As you are pushing up on the filter on the nipple begin turning the filter clockwise and begin to thread it on the filter
Tighten firmly by and hand and then use the Remove and Install Wrench to firmly tighten the filter. Note: you may tighten
it well as the wrench is great for both remove and install with a bit of practice.
Now reconnect the water sensor wire with your left hand and close the wire keeper with the wire in it.
Now loosen the plastic bleeder on the top of the filter head three full turns (this may be a grey or black plastic piece with
a slot through the center of it) but do not remove.
Next begin to pump on the hand pump round metal part on the top of the filter head. It will create suction and bring fuel
from the tank to fill the filter up from the bottom and you will know when you are done pumping as a bit of fuel will start to
leak past the plastic slotted bleeder. Stop pumping.
This process may take 30 pumps or less. Please let the pump come up each time as it needs to travel a full stroke to get
maximum quantity each time.
Remove all rags or any tools from the engine bay. Clean hands completely of any diesel and start the engine.
If you have performed all task's correctly you will not set a code 0380 which is low fuel rail pressure caused by a leaking
o-ring that is not firmly up against the filter head. This will be remedied by either lowering the filter a bit to be sure the o-
ring is in place or just tightening the filter more.
Note : When the factory installs the filter it is installed with the o-ring dry. Wetting the o-ring on replacement the first time
with a bit of grease or motor oil will ease filter removal.
Note: The Dmaxwrenchkit's remove and install wrench jaws may remove a small amount of paint from the filter housing
when squeezing it on the filter. Be balanced so you don’t pinch the filter too hard.
On install of filter, to avoid setting a code (low fuel rail pressure) be sure to firmly tighten the filter so that the suction of
the CP3 pump does not bring air into the filter and cause the engine to stall. If engine stalls after filter install recheck all
seals and check filter tightness.
Tip: Fast track
For a drip free clean removal attach a piece of vinyl tube to the drain valve on the water sensor unscrew the drain valve
a bit and let the filter drain for about 15-20 minutes before removal. Be sure to unscrew the filter a bit to break the
After draining completely, slowly loosen and when fully unscrewed and lower to the frame rail then in the wheel well pry
back the fender plastic and slip the filter with the water sensor attached. Swap everything with new o-rings onto the new
filter and pull back the fender plastic and set on the frame rail.
Then reach down inside the engine bay and grab the filter and bring it up and push it onto the filter housing so the
rubber center piece holds the filter in place. Tighten by pushing upward and threading the filter snug. Then bring in the
filter wrench and tighten it up. Viola! You’re done. Reconnect the sensor connector, bleed and pump up the hand pump
till hard after tightening the bleeder screw and start it up.
Email for assistance firstname.lastname@example.org and provide your phone number and you will promptly get a call to assist
with the wrench's operation.
Wish you the best success and remember you can do this, and it is easier the second time.
|01-12 Duramax Diesel Fuel
Filter replacement Instructions