How Do I Change a Duramax Fuel Filter?
The Duramax diesel engine comes installed in GM model trucks. Duramax engines come equipped with a fuel filter that is responsible for keeping clean diesel flowing to the engine. The fuel filter has an inner filter made up of fibers that catch and hold impurities in the diesel. Once the diesel has flowed through the inner filter, the clean diesel then flows to the fuel injectors. The fuel injectors then disburse the diesel into the engine.
Other People Are Reading
Things You'll Need
- Flat-head screwdriver
- Drip pan
- Fuel filter strap wrench
- Pliers
- Fresh diesel
- New fuel filter
Instructions
-
-
1
Park the vehicle in a well-ventilated location. Turn the steering wheel all the way to the right so that the wheels will be positioned to the far right. Then, turn the engine off and open the hood.
-
2
Move to the front passenger-side wheel compartment and remove the plastic guard in the back of the compartment. The plastic cover is connected by small plastic clips. Pry the clips through the holes on the plastic cover using the flat-head screwdriver. Pull the cover out of the wheel compartment and place it on the ground. You can now access the fuel filter through the back of the wheel compartment.
-
-
3
Locate the water sensor on the bottom of the fuel filter. Follow the wires from the bottom of the fuel filter to where they connect to another plug near the passenger-side valve cover. Unplug the end of the water sensor wire and let the wire hang straight down below the fuel filter.
-
4
Position the drip pan underneath the vehicle in the general location of the fuel filter, to catch the excess diesel.
-
5
Slide the fuel filter strap wrench about halfway up the fuel filter. Slowly turn the fuel filter counterclockwise until it loosens from the fuel filter housing threads. Once the filter is completely loose, finish unscrewing it with your hand. Be careful, as it will be full of diesel. Once the fuel filter disconnects from the housing threads, lower it to the frame rail and set it upright.
-
6
Move back to the top of the engine and pull the fuel filter out of the engine compartment through the top of the engine. Pour the diesel out into the drip pan. Unscrew the water sensor from the bottom of the fuel filter using pliers. Turn the water sensor counterclockwise to loosen and remove.
-
7
Pull the old O-ring off the water sensor base and slide on the new O-ring. Screw the water sensor onto the bottom of the new fuel filter.
-
8
Fill the new fuel filter completely with fresh diesel. Dab a generous amount of diesel around the O-ring at the top of the filter. This will lubricate the O-ring and help the fuel filter seat in its housing properly.
-
9
Carefully lower the fuel filter through the top of the engine down to the passenger-side frame rail. Move back to the front passenger-side wheel compartment. Reach in and position the fuel filter up to the housing threads. Screw the fuel filter onto the threads by turning it clockwise. Once it is tight enough that it can't be turned with your hands anymore, slide the strap wrench back on about halfway, and turn the fuel filter another half turn to completely seat the new fuel filter on the housing. Remove the strap wrench. Reconnect the water sensor wire back to the plug near the passenger-side valve cover.
-
10
Move back to the top of the engine and prime the fuel filter by opening the relief valve on the top of the fuel filter. The relief valve is a round black cap that can be turned about one quarter of a turn counterclockwise to open. Once the relief valve is open, pump the primer valve from the top of the fuel filter housing in and out until the diesel comes out of the relief valve. Once a steady stream of diesel comes out after each pump, close the relief valve by turning the cap one quarter of a turn clockwise.
-
11
Turn the ignition key on for 10 seconds. Crank the engine and let it run for about 30 seconds to circulate the fuel through the fuel system. Turn the engine off.
-
12
Reinstall the fastener onto the back of the front passenger-side wheel compartment. Slide the drip pan out and shut the hood.
-
1
Tips & Warnings
The purpose of opening the relief valve on top of the fuel filter housing is to not only allow the diesel to come out but also allow the air a place to come out.
The fuel filter can also be removed by using fuel filter pliers or a large pair of channel locks.
If the fuel filter is not properly primed with diesel, it can cause the engine to vapor-lock and not crank at all.
Do not smoke or allow open flames around diesel.
Wear protective glasses when replacing the fuel filter.
Never tighten a fuel filter with fuel filter pliers or channel lock pliers. This can puncture the fuel filter.
References
Resources
- Photo Credit IT Stock Free/Polka Dot/Getty Images
