Changing The Diesel Fuel Filter In Your 2008 F350: Step-By-Step Guide

Changing the fuel filter on a diesel vehicle can be a messy job, but it's not too complicated and can save you a lot of money. This guide will take you through the process of changing the fuel filter on a 2008 F350 with a 6.4L engine.

The first step is to gather your supplies and tools. You'll need a new fuel filter kit, a bucket or tub to drain the fuel, and a coffee can or leak-proof container for disposing of the old filter. For tools, you'll need a 36mm socket, a 6mm Allen wrench, and a 24mm socket or 1/2 drive ratchet.

Next, locate the primary fuel filter under the driver's side door on the frame rail. Place your tub or bucket beneath the fuel pump and locate the allen plug on the side of the fuel pump. Remove the allen plug with the 6mm allen wrench and drain the fuel/water completely.

Now, use the 36mm socket to remove the large black end cap and pull out the old filter and o-ring. Dispose of these parts properly, and install the new primary fuel filter and o-ring. Tighten the cap securely and reinstall the allen plug.

Finally, locate the secondary fuel filter in the engine compartment. Using the 24mm socket or 1/2 ratchet, remove the black top cap and take out the old filter and o-ring. Drain any excess fuel from the housing and insert the new secondary filter. Reinstall the black top cap and tighten it to the specified torque.

Before starting your engine, don't forget to prime the fuel system by turning the ignition to the 'Run' position for 30 seconds, repeating this process at least six times to bleed out any air.

Draining the fuel and changing the filter

To drain the fuel and change the filter on a 2008 F350 with a 6.4L engine, you'll need to gather some tools and materials. These include a 36mm socket, a 6mm Allen wrench, a 24mm socket or 1/2" drive ratchet, a bucket or tub for draining the fuel, and a coffee can or leak-proof container for transporting the old filter for disposal. You'll also need a new fuel filter kit, which you can purchase online or at an auto parts store. Motorcraft and Racor are two recommended brands.

Once you have your tools and materials ready, follow these steps:

• Place the bucket or tub beneath the fuel pump, which is located under the driver's door on the frame rail.
• Locate the allen plug on the side of the fuel pump. This is a small, brass plug.
• Using the 6mm Allen wrench, remove the allen plug.
• With the bucket in place, drain the fuel/water completely.
• Using the 36mm socket, remove the large black end cap on the end of the fuel pump that is nearer to the engine. The fuel filter will slide out along with the cap.
• Pull the old filter and the o-ring from the cap and dispose of them properly. You can place the old filter in a lidded coffee can or leak-proof plastic bag and take it to a recycling center that accepts scrap metal.
• Install the new primary fuel filter into the cap. The new filter will snap into place once seated properly.
• Install the supplied o-ring into position on the end cap.
• Insert the new filter and cap section into the fuel pump, using the 36mm socket to tighten the cap securely. Torque it to 19lb. per ft.
• Reinstall the allen plug, being mindful not to over-tighten or cross-thread it.

Now that you've drained the fuel and changed the primary fuel filter, you can move on to changing the secondary fuel filter, which is located in the engine compartment.

Tools required for the job

To change the fuel filter on a 2008 F350 with a diesel engine, you will need a variety of tools to get the job done safely and efficiently. Here is a detailed list of the tools required:

First and foremost, you will need a set of wrenches. This includes both standard and metric sizes, as you will encounter different fastener types throughout the process. Ensure you have a range of sizes to accommodate various fasteners.

A quality set of screwdrivers is also essential. Both Phillips and flat-head types will be needed, again in various sizes to match the screws you will encounter.

A socket set, including both shallow and deep sockets, will be required. This job calls for a range of socket sizes, so ensure your set is comprehensive. You will also need a ratchet and extension bars to access tight spaces.

Pliers, including both standard and needle-nose varieties, will be needed for gripping and turning various components. Having a pair of adjustable pliers, such as water pump pliers, can also be useful for turning larger components.

You will also need a jack and jack stands to safely raise and support the vehicle. Do not attempt this job without first ensuring the vehicle is securely lifted and supported to prevent injury.

A new fuel filter is also required, of course. Ensure you have the correct replacement part before starting the job.

Finally, you should have some clean rags or shop towels on hand to wipe up any spills or leaks and some disposable gloves to keep your hands clean during the process.

The location of the primary and secondary filters

The 2008 F350 6.4L has two fuel filters. The primary fuel filter is located in the Horizontal Fuel Conditioning Module (HFCM), which is mounted to the driver's side frame rail. The HFCM also contains the water-fuel separator. The secondary filter is positioned on the top side of the engine, just to the right of the engine oil filter.

To access the primary filter, you will need to locate the HFCM on the driver's side frame rail between the engine and fuel tank. The filter cap can then be removed with a 36mm socket. The fuel filter will generally come out with the cap, but if it does not, you can remove it manually.

The secondary filter is located on the top of the engine. To access it, remove the cap with either a 24mm socket or a 1/2-inch square drive.

The order in which to change the filters

To change the fuel filters on a 2008 F350, you will need to relieve the pressure in the fuel system, remove the old fuel filter, and install a new one. Here is the order in which you should perform these steps:

Relieving the Pressure in the Fuel System:

• Locate your vehicle's fuse box, which is usually in the interior or under the hood.
• Refer to your vehicle's owner's manual to identify the fuse that powers the fuel pump, and remove it using needle-nose pliers or plastic tweezers.
• Ensure your vehicle is not in gear. For automatic vehicles, make sure it is in park, and for manual transmission vehicles, ensure it is in neutral with the parking brake engaged.
• Start the engine and let it run for a minute or two before shutting it off.
• Re-insert the fuel pump fuse.

Disconnecting the Battery and Locating the Fuel Filter:

• Disconnect the negative terminal on the battery.
• Locate the fuel filter. Refer to your vehicle's service manual to determine its location, as it could be along the fuel line on the bottom of the car or in the engine bay.
• If the fuel filter is located on the underside of your vehicle, jack up the car to access it and place a jack stand underneath for safety.

Removing the Old Fuel Filter:

• Place a bowl or bucket beneath the fuel filter to catch any fuel that may spill out.
• Remove the clips holding the fuel filter in place using a flat-head screwdriver.
• Slide the fuel lines away from the filter and towards the bowl or bucket to catch any spilled fuel.
• Slide the fuel filter out of its bracket by pushing it towards the front or back of the car, depending on how it sits in the bracket.

Installing a New Fuel Filter:

• Compare the new fuel filter to the old one to ensure they appear the same in terms of outside diameter, nozzle size, and bracket fit.
• Slide the new fuel filter into the bracket.
• Fasten the fuel filter to the fuel line by sliding the fuel lines onto the front and back of the filter and securing them with the plastic clips.
• If you had to jack up your vehicle, lower it to the ground and reconnect the battery.

Final Steps:

• Turn the ignition to the "ON" position for a few seconds, then turn it back to the "OFF" position. Repeat this step once more to bring pressure back into the fuel system.
• Check for leaks under your vehicle and start the engine. If there are no leaks, you're good to go!

How to prime the fuel system

To prime the fuel system of a 2008 F350 diesel, follow these steps:

First, ensure that the fuel tank is not full. It is recommended to change the filters when you have less than a quarter of a tank of fuel. This will prevent fuel from flowing freely and reduce the risk of a mess.

Next, locate the fuel filter. For the 2008 F350 6.4L, there are two fuel filters: one mounted on the engine and one mounted on the inside of the frame rail under the driver's side. Place a rag over the frame rail to catch any diesel fuel that may leak when removing the filter cap.

Now, use a 36mm socket to remove the cap from the engine-mounted filter. Pull it out slowly, allowing the fuel to drain back. Then, open the drain on the HFCM (located under the driver's side) and let the fuel drain into a container. Remove the cap from the HFCM filter using the same socket size.

Clean both filter caps and mounting areas thoroughly. Lubricate the O-rings with fuel and install the new filters into their caps. Ensure that the O-rings are properly seated and lubricated before tightening the caps. The recommended torque for the caps is 20 ft-lbs for the HFCM filter and 18.5 ft-lbs for the engine-mounted filter.

Finally, to prime the system, cycle the key without turning on the engine for at least 30 seconds, then turn it off. Repeat this process at least 6 times to purge air from the system.

Some people recommend leaving the driver's side door open during this process, as it may help with priming. After priming, start the engine and check for any fuel leaks.

Frequently asked questions