The Ford 3C3Z-9C165-AA Fuel Filter Assembly Seal Kit is a genuine Motorcraft/Ford OEM service gasket and O-ring package engineered specifically for 2003–2007 Ford Super Duty trucks, Excursions, and E-Series vans equipped with the 6.0L Powerstroke diesel engine. Designed to service the secondary engine-mounted fuel filter bowl and its integrated fuel pressure regulator housing, this factory-original kit provides exact-fit fluorocarbon elastomeric seals that eliminate stubborn diesel seepage, maintain regulated fuel pressure, and prevent air infiltration into the secondary fuel system.

Quick Specs & Kit Inclusions

• Application: Engine-mounted secondary fuel filter bowl and pressure regulator housing reseal
• Seal Material: High-grade, fuel-resistant fluorocarbon (Viton) and specialized synthetic elastomers formulated for ultra-low sulfur diesel (ULSD) and biodiesel blends
• Manufacturing Standard: Genuine Ford Original Equipment Manufacturer (OEM) component
• Emissions Status: 50-state legal (direct OE replacement part)
• Direct Interchange Part Numbers: Ford 3C3Z-9C165-AA, Motorcraft 3C3Z9C165AA
• What's in the Box: Complete genuine Ford fuel bowl and regulator housing gasket and O-ring set (including fuel pressure regulator housing face seal, internal regulator valve grommet/seals, and fuel bowl interface O-rings)

Problem Solved: Curing Fuel Bowl Weeping, Pressure Bleed-Off & Hard Starts

A common nuisance on 6.0L Powerstroke engines is fuel pooling in the engine valley beneath the secondary fuel filter housing. Over thousands of miles and severe engine heat cycles, the factory rubber seals on the fuel bowl and the fuel pressure regulator (blue spring housing) flatten, harden, and weep raw diesel. This seepage causes strong underhood fuel odors, collects dirt in the valley, and can degrade wiring harnesses and cooling hoses below. Furthermore, worn internal regulator seals bleed off regulated fuel pressure and allow air into the secondary fuel circuit during key-off periods, leading to fuel drain-back, extended hot or cold cranking times, and lower injector supply pressure. Installing the genuine Ford 3C3Z-9C165-AA kit restores factory-tight hydraulic containment using precise OEM-spec durometer materials that withstand modern diesel chemistry.

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
• 2004–2008 Ford F-650 / F-750 Super Duty (VT365 Engine)
• 2003–2007 International / Navistar VT365 & MaxxForce 5 Engines

Safety & Depressurization: Park the vehicle on level ground and switch off the ignition. Disconnect both negative battery cables. Relieve residual fuel pressure by slowly loosening the secondary fuel filter cap using a 24mm or 15/16" socket, allowing trapped pressure to bleed off safely. Access & Removal: Place absorbent shop towels in the engine valley around and under the fuel filter bowl. Using a T27 Torx driver, remove the retaining screws securing the fuel pressure regulator cover to the side of the secondary fuel filter housing. Carefully pull the regulator cover back, catching the regulator spring and brass plunger piston as they release. Disassembly & Cleaning: Remove the old regulator housing face seal, internal valve stem grommet, and associated fuel bowl passage O-rings using a non-marring brass or plastic pick. Clean all mating surfaces, the spring cavity, and the regulator plunger thoroughly using brake cleaner and lint-free shop cloths; inspect the housing surfaces for gouges, pitting, or particulate grit. Seal Lubrication & Placement: Lightly coat all new Ford 3C3Z-9C165-AA seals and O-rings with clean engine oil or clean diesel fuel prior to installation. Seat the internal regulator seat grommet squarely into the housing bore. Position the molded outer perimeter seal into the machined channel of the regulator plate, verifying it lies completely flat without twisting or stretching. Reassembly: Reinstall the brass regulator piston, sleeve, and spring into the housing cavity. Hold the regulator cover flat and square against the fuel filter bowl body, compressing the spring by hand to ensure the outer seal stays seated in its groove and does not pinch. Torque Target: Start all T27 Torx retaining screws by hand to ensure proper thread alignment. Tighten the screws evenly in an alternating, crisscross pattern to 45–55 in-lbs (5–6 Nm) using a 1/4-inch drive torque wrench. Do not over-torque, as the aluminum housing threads strip easily. Filter Cap Torquing: Reinstall the secondary fuel filter and cap, lubricating the cap O-ring with clean diesel. Torque the cap to 19 ft-lbs (25 Nm). Fuel Priming & Leak Verification: Reconnect both battery cables. Turn the ignition key to the "RUN" position for 30 seconds without cranking to let the electric lift pump fill the bowl and purge air through the regulator. Repeat this cycle 3 to 4 times. Inspect the regulator housing perimeter and valley thoroughly for zero leaks before starting the truck.