Changing The Fuel Filter Head On A Duramax

Changing the fuel filter head on a Duramax engine is a straightforward process that can be done at home with the right tools and knowledge. The fuel filter is located on the passenger side of the engine, below the air intake tube. The first step is to remove the centre air intake tube and the passenger-side inner fender. Next, the water-fuel separator drain valve at the bottom of the fuel filter is opened, and the bleed screw at the top of the fuel filter housing is loosened to drain the water and fuel into a container. It is important to properly dispose of this mixture. The water-in-fuel sensor electrical connector is then disconnected, and the fuel filter is rotated counter-clockwise and removed. The old gasket, if stuck to the fuel filter head, should be removed. The water-in-fuel sensor assembly is then removed from the bottom of the filter using a wrench, deep socket, or pliers. A new o-ring and gasket should be lubricated with clean engine oil and installed. Finally, the new fuel filter is installed, and the bleed valve is opened to prime the fuel filter. The engine can then be started, and any leaks can be checked.

Remove the air intake tube

To remove the air intake tube, you'll need to be sitting by the passenger side tire, looking at the fender well. Using a panel clip remover, remove the pins that are holding the inner fender well liner to the truck. You can then set the liner aside.

Now, you should be able to see the fuel filter. Disconnect the WIF (Water In Fuel) connector and let it hang. You can then unscrew and remove the fuel filter. You might be able to do this with your hands if you are strong enough, otherwise, use a strap wrench.

Once the fuel filter is removed, you can dispose of its contents properly. Using a WIF wrench or channel locks, remove the WIF sensor. The new filter should come with new O-rings, so make sure you remove and discard the old ones.

Now, you can start to put everything back together. Lubricate the new O-rings with some 2-stroke oil and don't be shy about using it. Lubricate the outer edge of the filter where the O-ring will be placed. Also, don't forget to replace the little O-ring on the WIF sensor. Lubricate this too.

With the fuel filter and WIF sensor back together, you can put the filter back into the truck. This part can be a little frustrating as it is an awkward position, and it's hard to get the filter threaded on. Be patient and it will thread its way on. Tighten down the filter as recommended (1/3 to 1/2 turn after the seal has made contact).

Now, go back to the engine and look at it from under the hood. You will see the filter pump and bleeder screw. Loosen the bleeder screw with a 1/2-inch nut driver (do not take it out all the way, just enough to let air out). With the bleeder screw loosened, you can begin priming the fuel filter. This will take about half a million pumps, so be patient! You will hear air coming out of the screw, and eventually, diesel fuel will come out. When this happens, press down on the primer pump and hold it, then tighten down the bleeder screw (warning: do not over-tighten). Keep pumping the primer until it gets very hard to pump – it will be almost impossible to pump anymore after that.

Finally, wrestle back on the inner fender liner and you're ready to start the truck.

Disconnect the water-in-fuel sensor

Disconnecting the water-in-fuel sensor is a crucial step when changing the fuel filter head on a Duramax engine. Here is a detailed guide on how to do this:

Firstly, locate the water-in-fuel sensor. It is usually found near the firewall on the passenger side of the engine. You will need to remove the inner fender well liner to access it fully. This can be done using a panel clip remover tool to remove the pins holding the liner in place.

Once the water-in-fuel sensor is located and accessible, the next step is to disconnect the electrical connector. Be careful not to damage the connector or the surrounding components. After disconnecting the electrical connector, you can proceed to remove the sensor itself.

For the next step, you will need a wrench, socket, or channel locks. Using your chosen tool, carefully remove the water-in-fuel sensor from the fuel filter. Be gentle, as these parts can be delicate and prone to damage. Ensure that you do not overtighten or apply excessive force, as this may lead to damage or stripping of the threads.

Once the water-in-fuel sensor is removed, inspect it for any signs of damage. If the sensor is damaged, it is important to replace it with a new one. A damaged sensor should not be reused, as it may lead to inaccurate readings or further issues.

If you are installing a new water-in-fuel sensor, make sure to lubricate the O-ring with clean engine oil before installing it. This will help create a tight seal and prevent leaks. Tighten the new sensor by hand, ensuring that it is secure but being careful not to overtighten it.

Finally, reconnect the electrical connector to the new or existing water-in-fuel sensor. Ensure that the connection is secure and that the wiring is not tangled or damaged.

By following these steps, you will successfully disconnect and replace the water-in-fuel sensor, which is an essential part of changing the fuel filter head on a Duramax engine.

Drain the water-fuel separator

To drain the water-fuel separator, first, locate the water-fuel separator drain valve at the bottom of the fuel filter. Then, open the bleed screw at the top of the fuel filter housing. Once the bleed screw is open, open the water separator drain valve and drain the water-fuel into a container. Remember to properly dispose of the drained water-fuel.

It is recommended to remove the passenger side inner fender for complete and easy access to the fuel filter housing assembly. To remove the fender, use a trim fastener removal tool or a flathead screwdriver to remove the plastic body clips and two 10mm bolts holding it in place.

Remove the passenger side inner fender

To remove the passenger side inner fender of a Duramax, you will need a panel clip remover or a flathead screwdriver. This will be used to remove the plastic body clips and two 10mm bolts holding the fender in place.

First, remove the pins that are holding the inner fender well liner to the truck. You can do this with a panel clip remover, or a flathead screwdriver if you don't have one. With all the pins removed, and the wire harnesses pulled out of the liner, you can set the liner aside.

Now you will be able to access the fuel filter from the passenger side. Disconnect the WIF (Water-in-Fuel) connector and let it hang. You can now unscrew and remove the fuel filter. This can be done by hand if you are strong enough, or with a strap wrench.

Install the new fuel filter

To install the new fuel filter, you should first lubricate the new o-ring with clean engine oil and install it onto the new fuel filter. Do not overtighten. Lubricate the new gasket with clean engine oil and install it at the top of the fuel filter assembly.

Next, install the new fuel filter, ensuring that the water-in-fuel sensor connector does not become entangled with its surroundings. Install by hand only, do not use tools to tighten.

Now, locate and open the bleed valve towards the driver's side of the fuel priming pump. You can remove the bleed screw for inspection of the o-ring if you wish.

Repeatedly pump the plunger on the top of the fuel filter housing until all air escapes and diesel fuel begins to flow out of the bleed screw orifice. Immediately close the bleed screw; do not overtighten, the screw is plastic. Clean up any spills so that leaks can be easily detected.

Finally, reinstall the inner fender and intake tube. Start the engine and check for leaks. The engine will run rough for the first 30 seconds. If it doesn't smooth out after about a minute, re-bleed the system and repeat the pumping process.

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