The Motorcraft F81Z-9H323-BB is an OEM fuel pressure relief cap for the 1999–2003 7.3 Powerstroke fuel filter bowl. It holds the fuel pressure regulator spring, brass poppet, and poppet seal in place on the driver side of the filter housing. Motorcraft lists it under part number CM-5016, and it replaces the earlier F81Z-9H323-BA revision.

A cracked plastic cap, stripped threads from a previous service, or a fuel leak running down the side of the filter bowl is what this cap fixes. It maintains correct seat pressure on the internal relief valve to keep fuel pressure regulated before fuel feeds into the cylinder heads. It is the replacement cap only.

It fits 1999–2003 7.3 Powerstroke trucks, Excursions, and E-Series vans.

Fitment

• 1999–2003 Ford F-250 Super Duty 7.3L Powerstroke
• 1999–2003 Ford F-350 Super Duty 7.3L Powerstroke
• 1999–2003 Ford F-450 Super Duty 7.3L Powerstroke
• 1999–2003 Ford F-550 Super Duty 7.3L Powerstroke
• 2000–2003 Ford Excursion 7.3L Powerstroke
• 1999–2003 Ford E-Series Vans 7.3L Powerstroke
• Direct fit on factory fuel filter bowl
• Replacement cap only

Relieve fuel bowl pressure and catch drain fuel before removing the old cap. Take care not to lose the internal regulator spring or poppet valve when unscrewing the mounting bolts. Torque evenly to avoid distorting the cap seal.