Changing Fass Fuel Filters: A Step-By-Step Guide For Duramax Engines

Changing the fuel filters on a Chevy or GMC Duramax engine can be done by unscrewing the old filters and screwing in the new ones. The FASS filter is a combination of the diesel lift pump and fuel filtration system. It is important to change the filters regularly, as a clogged filter can impact the engine's performance. The manufacturer recommends changing the standard filter every 15,000 miles and the XL filter every 30,000 miles. However, some users have reported success with alternative methods, such as using a rag to wrap the service port and then pumping.

Unscrewing the old filter

To begin the process of unscrewing the old filter, locate the fuel filters. They are usually found close to each other and are easily visible. Once you have located them, you will need to gather the appropriate tools to begin the unscrewing process. Make sure you have a bucket or container nearby to catch any fuel that may leak during the process.

The next step is to place the bucket or container under the filter to catch any fuel that may spill or leak. This is an important step as it will help to prevent any fuel from getting on your driveway or garage floor. It is also recommended to have some rags or towels nearby to wipe up any spills or leaks.

Now, it's time to start unscrewing. Grip the filter firmly and turn it counterclockwise to unscrew it. You may need to use a wrench or a similar tool to get a good grip and apply the necessary force. Be careful not to apply too much force, as you don't want to damage the filter housing or any surrounding components.

Once the filter is unscrewed, slowly and carefully remove it from the housing. Again, be cautious of any fuel that may spill or leak during this process. Have the rag or towel handy to wipe up any spills immediately. Place the old filter in the bucket or container to catch any remaining fuel and to prevent further messes.

At this point, you have successfully unscrewed and removed the old filter. It is now safe to dispose of the old filter properly, following your local disposal guidelines for fuel filters. Remember to handle the old filter with care, as it may still contain some fuel residue.

Filling the new filter with diesel

Before you begin, ensure you have the necessary tools and safety gear, including gloves and eye protection. It is also recommended to have a bucket nearby, as this process can get messy. Start by locating the fuel filters. In a Duramax engine, there are typically two fuel filters: one between the fuel tank and the engine, and the other closer to the engine. Both filters need to be changed, so identify and access them first.

Once you've located the filters, it's time to fill them with diesel. Remove the old filters by unscrewing them and set them aside. Take your new filters and fill them with diesel fuel. You can do this by pouring diesel into the opening of the filter until it's about two-thirds full. It is important to handle the diesel carefully and avoid spilling it. Make sure you are in a well-ventilated area during this process.

After filling the new filters, screw them securely into place, ensuring they are tight. Now, you can run the pump. During this process, you may need to bleed the air bubbles out of the system to ensure there is no air left in the fuel system. This step may vary depending on your specific Duramax model, so refer to your owner's manual or seek guidance from a mechanic if needed.

Finally, start the engine and let it idle for a few minutes. Check for any leaks or unusual noises. If everything seems normal, take your vehicle for a short test drive to ensure the engine is running smoothly.

Remember, it is important to change your Duramax fuel filters regularly, as recommended by the manufacturer. This will help maintain optimal engine performance and fuel efficiency, as well as extend the lifespan of your fuel injectors.

Tightening the new filter

When tightening the new filter, it is important to follow the correct procedure to ensure a secure and proper fit. Here are some detailed instructions to guide you through the process:

Before starting, ensure you have the correct replacement filter for your FASS fuel filter system. The manufacturer recommends specific filters for their systems, so using the recommended filter type is crucial. The type of filter will determine the tightening procedure and torque specifications.

First, check that the gasket on the filter is in good condition and properly seated. A damaged or misaligned gasket can cause fuel leaks, so take care when handling it. You can lightly coat the gasket with fuel before installing the new filter. This will help create a better seal and protect the gasket during installation.

Next, screw the new filter into place by hand. Ensure that it is properly aligned and seated in the correct position. Tighten the filter securely, but be careful not to overtighten it. Overtightening can damage the filter, the gasket, or the threads on the filter housing.

For the FASS Titanium Series filters, it is recommended to tighten the filter until it is snug and then give it an additional quarter to half turn. Do not overtighten, as this can damage the filter and affect its performance.

If you are using a torque wrench to tighten the filter, refer to the manufacturer's specifications for the recommended torque settings. Different filters will have different torque specifications, so ensure you are using the correct value for your specific filter.

Once the new filter is tightened, check for any fuel leaks around the gasket or the filter housing. A properly tightened filter should not leak. If you notice any leaks, carefully retighten the filter, ensuring that the gasket is seated correctly.

Finally, it is important to prime the new filter before starting the engine. Follow the manufacturer's instructions for priming the FASS fuel pump to ensure that the filter is fully prepared for use. This may involve running the pump, bleeding air bubbles from the system, or other specific steps.

Remember to dispose of the old filter properly and according to local regulations. Used fuel filters can contain residual fuel and contaminants, so handle them with care and recycle them whenever possible.

Replacing the wire

To replace the wire, first, locate the fuel filter housing. This is usually found in the engine bay, near the firewall on the driver's side. Once you have located the fuel filter housing, disconnect the negative battery terminal to prevent any accidental short circuits during the replacement process.

Using a wrench, loosen and remove the fuel filter housing cap. Set the cap aside in a safe place. You will now be able to see the fuel filter inside the housing. Gently pull it out and set it aside as well.

Take your new fuel filter and insert it into the housing, ensuring that it is properly seated and secure. Screw the housing cap back on tightly, using your wrench to avoid over-tightening. Reconnect the negative battery terminal.

Finally, start the engine and check for any signs of fuel leaks around the fuel filter housing. If there are no leaks, turn off the engine and re-tighten the fuel filter housing cap with your wrench if necessary.

It is important to note that you should always refer to your vehicle's service manual for specific instructions on replacing the fuel filter, as procedures may vary depending on the make and model of your Duramax engine. Additionally, always exercise caution when working with fuel system components, as diesel fuel is highly flammable.

Priming the filter

To prime the FASS filter, you must first fill both filters and screw them on. Then, run the pump and crack the front filter (not the water separator) so that fuel leaks or sprays out. Tighten the filter when a steady flow of fuel and a steady sound come from the pump. This process is messy and will require a bucket to catch the leaking fuel. It is important to bleed all the air out of the FASS filter to ensure it runs as quietly as possible.

You can also replace all the filters, filling the FASS filters and leaving the stock filter empty. Then, remove the bleeder screw and run the FASS filter until a steady flow of fuel comes out. Ensure there are no air bubbles, and make sure you have at least 5 gallons of fuel in the tank to avoid seeing small air bubbles. This method will also be very messy.

Another option is to wrap the service port with a rag or two and push the Schrader valve with a screwdriver while pumping. This method is less messy and will ensure there is no hesitation to start.

It is important to note that the FASS filter should be primed before use to ensure optimal performance.

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