Changing Your Duramax Fuel Filter: Step-By-Step Guide

Changing the fuel filter on a Duramax engine is a relatively simple task that can be done in a few easy steps. The fuel filter is located on the passenger side of the engine, underneath the hood near the firewall. To change the fuel filter, first pop the hood and remove the inner fender well liner by taking out the pins holding it to the truck. Disconnect the Water In Fuel (WIF) sensor connector and let it hang. Now, the fuel filter can be unscrewed and removed. It is important to note that the contents inside the filter should be disposed of properly. The WIF sensor can be removed using a wrench or channel locks, and it is recommended to lube up the O-rings with 2-stroke oil before reassembling. The new filter can then be installed, ensuring that the WIF sensor connector is not entangled. The bleeder valve can be located and opened, and the plunger on the top of the fuel filter housing can be pumped repeatedly until all air escapes and diesel fuel begins to flow out. The bleeder valve can then be closed, and the inner fender and intake tube can be reinstalled. Finally, the engine can be started, and it is recommended to check for leaks.

The fuel filter is located on the passenger side of the engine

Now, disconnect the WIF (Water-in-Fuel) connector and let it hang. You can then proceed to unscrew and remove the fuel filter. This can be done by hand if you are strong enough, or with a strap wrench if you need more leverage. Be careful not to spill any fuel during this process.

Once the fuel filter is removed, properly dispose of the contents inside. Use a WIF wrench or channel locks to remove the WIF sensor. Remember to replace the old o-rings with the new ones provided with the fuel filter. Lubricate the o-rings with 2-stroke oil or clean engine oil before installing the new fuel filter.

The fuel filter is now ready to be placed back into the truck. This can be a little tricky due to the awkward position, but be patient and thread the filter back into place. Tighten the filter as recommended (1/3 to 1/2 turn after the seal has made contact).

Now, locate the filter pump and bleeder screw under the hood, on the driver's side of the fuel priming pump. Loosen the bleeder screw slightly and begin priming the fuel filter. You will need to pump it multiple times to remove all the air. Eventually, diesel fuel will start to come out. Tighten the bleeder screw, clean up any spills, and you're almost done!

Finally, reinstall the inner fender liner and start the engine. Check for leaks and ensure that the idle smooths out within 30 seconds. If the truck runs rough for an extended period, turn off the engine, re-bleed the system at the fuel filter housing, and check for leaks again.

You will need a panel clip remover, a Water In Fuel sensor wrench, a 1/2 inch Nut driver, and 2-stroke oil

To change your Duramax fuel filter, you will need a panel clip remover, a Water In Fuel (WiF) sensor wrench, a 1/2-inch Nut driver, and 2-stroke oil. These tools will help you access and manipulate the various components of the fuel filter housing and ensure a smooth replacement process.

The panel clip remover is a handy tool that assists in removing the pins holding the inner fender well liner to the truck. It efficiently removes the clips without causing damage to the surrounding areas. With the liner removed, you'll have better access to the fuel filter.

The WiF sensor wrench is used to remove the WiF sensor, which is installed in the fuel filter. The WiF sensor detects the presence of water in the fuel and sends a signal to the ECU or dashboard when the water level reaches a warning level. By using the WiF sensor wrench, you can safely detach the sensor from the fuel filter.

The 1/2-inch Nut driver is a crucial tool for loosening and tightening various nuts and bolts during the fuel filter replacement process. It provides the necessary torque and precision to work with these fasteners.

Finally, 2-stroke oil serves as a specialised lubricant for two-stroke engines. In the context of the Duramax fuel filter replacement, you will use the 2-stroke oil to lubricate the O-rings and other moving parts. This helps ensure a smooth operation, prevents metal-to-metal contact, and protects the engine components from wear and damage.

Loosen the bleeder screw with a 1/2 inch nut driver

To loosen the bleeder screw with a 1/2 inch nut driver, follow these steps:

First, locate the bleeder screw. It is located on the top of the fuel filter housing, towards the driver's side of the fuel priming pump. Once you have located it, use a 1/2 inch nut driver to loosen the screw. It is important to note that you should not remove the screw completely, just loosen it enough to let air out.

With the bleeder screw loosened, you can now prime the fuel filter. This may take some time and patience, as it can take up to half a million pumps to prime the filter fully. You will know that you have successfully primed the filter when you hear air coming out of the screw, followed by diesel fuel. Once you see diesel fuel coming out of the screw, it is time to move on to the next step.

Using your hand, tighten down the bleeder screw. Be careful not to over-tighten it, as this can cause damage. After tightening the screw, continue pumping the primer until it becomes very hard to pump. You will know that you have successfully primed the fuel filter when it becomes almost impossible to pump anymore.

And that's it! You have now loosened the bleeder screw with a 1/2 inch nut driver and primed your fuel filter. This is an important part of maintaining your Duramax engine and ensuring that it runs smoothly.

Prime the fuel filter

To prime the fuel filter on a Duramax engine, follow these steps:

Locate the fuel filter housing on the passenger side of the engine. The housing will have a built-in fuel plunger or primer pump for priming the fuel system. Remove the inner fender on the passenger side to access the fuel filter housing.

Locate the plastic bleeder screw on the primer cylinder's top. Crack the bleeder screw with a screwdriver or 13mm socket to release the air. Be careful not to overtighten the screw, as it is made of plastic.

Pump the primer cylinder until it becomes firm. You may need to do this several times to completely release the air from the fuel system. Continue pumping until fuel comes out of the bleeder screw and the engine starts to run. It may take a few cycles of starting and turning off the engine before it runs continuously.

If priming takes longer than a minute, your filter head may need to be rebuilt. Over time, the "O" rings can lose their sealing capacity, so you may need to replace them.

It is important to note that you should not put raw fuel directly into the filter, as it can damage the injectors. Always make sure to bleed the air out of the system before starting the engine to prevent additional strain and wear on the high-pressure injection pump.

Reset the Change Fuel Filter indicator

Resetting the "Change Fuel Filter" indicator on a Duramax engine can be done in two ways, depending on whether your truck has steering wheel controls or not.

For vehicles with steering wheel controls:

• Press and hold the select button for 5 seconds while the "FUEL FILTER LIFE" message is displayed.
• The message will appear on the Driver Information Center (DIC) for 10 seconds.

For vehicles without steering wheel controls:

• Turn the ignition key to the "ON" position without starting the engine. Do not press the pedals.
• Fully press the brake and accelerator pedals simultaneously and hold for 10 seconds.
• Turn the ignition key off. The system is now reset, and the message will no longer be displayed the next time the engine is started.

It is important to ALWAYS reset the "FUEL FILTER LIFE" system after changing the fuel filter.

Frequently asked questions