The 7.3L Power Stroke has a single fuel filter located near the front of the engine in the valley. It features a convenient drain valve and tube system that allows the housing to be drained remotely. Fuel filter replacement is a critical service procedure that protects the remainder of the fuel system and ensures fuel flow is not impeded due to a filter obstruction. Fortunately, replacing the filter is relatively simply for the 7.3L Power Stroke diesel and the procedure can be completed in as little as a few minutes. Note that the truck featured herein is a 1994.5 to 1997 generation F-Series. The service procedures are nearly identical for the later 1999 - 2003 Super Duty, although the filter/cap style is different.
7.3 Power Stroke Fuel Filter Part Numbers
| Part Description | Part Number |
| Fuel filter, 1994 - 1997 | Motorcraft FD-4595 Ford F4TZ-9N184-A |
| Fuel bowl cap, 1994 - 1997 | Ford F5TZ-9G270-A |
| Fuel filter, 1999 - 2003 | Motorcraft FD-4596 Ford F81Z-9N184-AA |
| Fuel bowl cap, 1999 - 2003 | Ford F81Z-9G270-BA |
How to Replace the Fuel Filter on a 7.3 Power Stroke Diesel
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• The fuel filter housing is located towards the front of the engine centered in the valley.
• Locate the metal fuel filter housing drain tube. On 1994 - 1997 engines it travels from the fuel filter housing vertically down the passenger side front of the engine block, ending just below the valve cover. A clamp just a few inches from the end of the tube secures it to the front of the engine block. It is roughly 5/16" in diameter. On 1999 - 2003 engines, the tube is in a similar location but on the side, not front, of the engine block. The location on later engines is easier to see than that on OBS trucks (fitting a camera in the region is near impossible). Keep looking, it is there.
• Attach a section of 5/16" fuel line (roughly 24 - 32 inches long for stock suspension/tires) to the drain tube so that it reaches the floor, then place the hose in a suitable fuel safe container. It seems easiest to access the tube from below the vehicle.
• The yellow fuel filter housing drain lever is located on the left hand side near the front of the assembly. Move the lever clockwise 90 degrees to begin draining the fuel filter housing.
• The fuel from the filter housing will now drain into your container. Watch the level of the container, as you're going to drain roughly 2 pints of fuel; you may need to close the valve, empty your container, then resume to keep it from spilling over.
• Once the housing has drained completely, remove the fuel filter cap. A screwdriver placed across the filter lid is the correct procedure for tightening and loosening the cap.
• The fuel filter can now be removed from the housing. Set the filter on a rag for transportation, as it will drip fuel. Remove and discard the old fuel filter cap gasket.
• Thoroughly coat the new fuel filter cap gasket with clean engine oil and install it on the housing (a new gasket is included with the replacement filter). Mind the orientation of the gasket, it is a V shape and the V should be facing into the lip of the housing, not upwards toward the cap.
• Remove the old fuel filter from the fuel filter housing cap and install the new one.
Note - Some aftermarket fuel filters come with their own cap and are not always compatible with the factory Ford replacement. If this is the case, you will need to purchase a new Ford style cap if you intend on installing a genuine Ford fuel filter.
You may also consider replacing the fuel filter cap periodically (every few filter changes); they tend to crack and cause an oily mess when they leak fuel. Over-tightening the fuel filter cap contributes to this problem, which we run into quite frequently.
• Reinstall the new fuel filter and tighten down the fuel filter cap. No need to overtighten, you can generally install it hand tight then give it a slight snug with a screwdriver to secure it.
• Close the fuel filter housing drain valve and remove the hose on the end of the drain tube. Start the vehicle and check for leaks. The truck is going to be difficult to start and will run rough until all the air is purged from the fuel system - this is entirely normal.