The Dorman 904-207 Fuel Injector O-Ring Kit is an OEM-standard replacement reseal pack engineered specifically for 2003–2010 Ford Super Duty trucks, Excursions, and E-Series vans equipped with the 6.0L Powerstroke diesel engine (as well as 4.5L Powerstroke and International Navistar VT365 applications). Designed to service two (2) HEUI fuel injectors, this complete reseal kit includes high-temperature fluorocarbon (Viton) external O-rings, upper high-pressure oil inlet D-rings, and solid copper combustion crush washers. It establishes positive fluid isolation between the 55–65 PSI fuel supply rail, the high-pressure oil circuit, and the high-temperature combustion chamber.

Quick Specs & Kit Inclusions

• Application: External seal and combustion washer refresh kit for two (2) G2.8 HEUI fuel injectors
• Elastomer Material: High-grade fluorocarbon (FKM / Viton) engineered to withstand continuous engine oil temperatures exceeding 250°F and resist diesel fuel degradation
• Washer Material: Solid, precision-stamped copper crush washer designed to deform evenly under injector clamp torque
• Quantity Note: Services two (2) fuel injectors; complete V8 engine reseal requires four (4) kits
• Emissions Status: 50-state legal (direct mechanical replacement sealing component)
• Direct Interchange Part Numbers: Dorman 904-207, Ford 3C3Z-9229-AA, Motorcraft CM-5055, Alliant Power AP0002, Navistar 1843682C91
• What's in the Box: (2) Upper Body O-Rings, (2) Lower Fuel Rail O-Rings, (2) High-Pressure Oil Inlet D-Rings / Cushion Seals, and (2) Copper Combustion Tip Crush Washers

Problem Solved: Curing Fuel Dilution, Hard Hot Starts & Combustion Blow-By

Whenever a fuel injector is extracted on the 6.0L Powerstroke, its elastomeric seals and copper washer take a permanent compression set and cannot be reused. Reinstalling injectors with old or degraded seals leads to severe engine malfunctions:

• Lower Copper Washer Failure: Causes hot combustion gases to blow past the injector nozzle, burning the lower O-ring, carbon-fouling the fuel rail, scoring the brass injector cup, and aerating the fuel system.
• Body O-Ring Breakdown: Allows pressurized diesel fuel to seep past the rocker carrier, diluting engine crankcase oil, thinning lubrication, and putting rod and main bearings at risk of catastrophic failure.
• High-Pressure Oil Inlet Seal Wear: Creates high-pressure oil leaks into the rocker box, leading to prolonged cranking, rough idling, or total no-start conditions when the engine is warm (sub-500 PSI ICP pressure).

The Dorman 904-207 kit permanently eliminates these cross-contamination failure points by restoring brand-new, factory-specification sealing surfaces.

Fitment

• 2003–2007 Ford F-250 Super Duty 6.0L Powerstroke Turbo Diesel
• 2003–2007 Ford F-350 Super Duty 6.0L Powerstroke Turbo Diesel
• 2003–2007 Ford F-450 Super Duty 6.0L Powerstroke Turbo Diesel
• 2003–2007 Ford F-550 Super Duty 6.0L Powerstroke Turbo Diesel
• 2003–2005 Ford Excursion 6.0L Powerstroke Turbo Diesel
• 2004–2010 Ford E-Series Vans (E-350 / E-450) 6.0L Powerstroke Turbo Diesel
• 2006–2010 Ford LCF (Low Cab Forward) 4.5L V6 Diesel
• 2003–2007 International / Navistar VT365 and VT275 Engines

Safety & Workspace Teardown: Turn off the ignition and disconnect both negative battery cables. Remove intake ducting, upper intercooler (CAC) piping, valve covers, and the high-pressure oil rail to access the fuel injectors. Injector Extraction & Old Seal Removal: Unbolt the hold-down clamp, disconnect the FICM electrical plug, and lift the injector from the cylinder head. Using a non-marring brass or plastic pick, remove the old external body O-rings and upper oil inlet D-ring. Remove the old copper washer from the nozzle tip (verify the old washer is not stuck at the bottom of the injector cup). Groove & Tip Cleaning: Inspect the injector body grooves and nozzle exterior. Clean thoroughly with lint-free towels and brake cleaner to remove dried carbon scale and oil sludge. Ensure no grit remains in the sealing ring lands. Bore Cleanout: Thoroughly clean and inspect the cylinder head brass injector cup using a dedicated bore brush and vacuum. The bottom copper seating face must be 100% clean, dry, and bare metal to guarantee a leak-free combustion seal. New Seal Installation: Lightly coat the new Viton body O-rings and upper oil inlet seal with clean 15W-40 or 5W-40 engine oil. Roll the new O-rings over the injector body into their respective upper and lower sealing grooves. Do not twist or spiral the rings during installation. Install the new high-pressure oil cushion D-ring squarely into the top inlet pocket of the injector. Slide the new copper crush washer over the nozzle tip, using a tiny dab of clean engine assembly grease to retain it during installation. Injector Insertion: Carefully guide the injector straight down into the cylinder head bore by hand, aligning the alignment dowels squarely. Firmly press down on the injector shoulder until it seats fully against the bottom of the cup. Hold-Down Torquing: Position the hold-down clamp over the injector and hand-thread the fastener into the cylinder head. Torque the hold-down bolt to factory specification: T40 Torx Bolt (18mm Dowel Heads): 24 ft-lbs (33 Nm) T45 Torx Bolt (20mm Dowel Heads): 26 ft-lbs (35 Nm) Final Assembly & Priming: Reinstall the high-pressure oil rail (torque oil rail bolts to 10 ft-lbs / 13 Nm), connect the FICM harness plugs securely, and reinstall the valve covers. Reconnect battery terminals, cycle the ignition key (KOEO) 4 to 5 times for 30 seconds each to prime and purge air from the fuel rails, then start the engine and inspect for smooth operation.