The Ford F81Z-18472-MAA is the heater-core inlet hose for a 1999–2003 7.3 F-Series without a coolant control valve. It is the hose into the core, with the plastic quick-connect and the O-ring already in the end. The outlet hose is YC3Z-18472-GA.

A brittle plastic end is a coolant leak in the engine bay and a heater that blows cold. Push it on until it clicks. A truck with a heater control valve uses a different inlet hose. The water-pump nipple is F81Z-18599-AA.

It fits 1999–2003 F-250 through F-550 trucks with the 7.3 and no control valve.

Fitment

• 1999–2003 Ford F-Series 7.3L
• Heater-core inlet
• No control valve
• Genuine Ford F81Z-18472-MAA
• O-ring in the end
• Outlet hose is YC3Z-18472-GA

Use the new clip. A reused clip will not lock. Top the degas bottle off and check it hot. A sweet smell in the cab is the core, not this hose.