The K&N PF-4000 is an inline, cartridge-style diesel fuel filter built for the Ford 7.3L Power Stroke. Its cellulose glass media is designed to trap rust, dirt, and scale before debris reaches the injection system, and the manufacturer says the carbon steel housing and rolled seam exceed OEM pressure requirements. That construction is the main reason to choose it over a generic economy filter, since a stronger housing and finer media help protect the injection pump and injectors on a truck that depends on clean, steady fuel delivery, especially when towing. Owners on user forums note that debris in the fuel line is a common cause of pump failure on these trucks.
Verify fitment before you order. The manufacturer's specs give a 4.313-inch length and a 6.563-inch outside diameter, but the year coverage published by different sources does not agree, so confirm your model year and engine with K&N. Owners on user forums discuss the 1999 to 2003 7.3L trucks most often, which is the range this filter is generally associated with. The manufacturer says the filter is designed to fit directly into the factory location, making it a practical choice for a stock-style replacement. Search terms buyers use include K&N PF-4000 7.3 Power Stroke fuel filter, 7.3 diesel inline fuel filter replacement, and OBS 7.3 fuel filter upgrade.
Yes. The manufacturer lists one fuel filter, one gasket, and one O-ring in the package.
The application is the Ford 7.3L Power Stroke diesel, but published year ranges vary between sources. Confirm your exact model year and engine with the manufacturer before ordering.
The manufacturer lists a 1 year limited warranty.
The manufacturer says it is designed to fit directly into the factory filter location.
Owners on user forums report that the filter bowl on the 7.3L uses left-hand threads and needs a 7/8-inch crowfoot wrench to remove. They also warn against pouring fuel into the bowl with the new filter left out, because unfiltered fuel would go straight toward the injectors. Instead, seat the new cartridge slowly so it absorbs fuel from the bowl without spilling. Owners further say the lift pump on these trucks runs when the engine cranks, so cranking is the way to prime the system after the change. Have a drain pan, clean diesel, and a new lid gasket and O-ring ready, and inspect the O-ring before reassembly.
