'80-96 Heater Core Installation diagram with labeled plenum and…

Heater Core Installation '80-96

Case is shown front-down. '87-early '88 use no vacuum motors inside the cab.

The boss just above the PLENUM TO COWL SEAL arrow is the drain duct.

To R&R the heater core:
1) with the engine cool, remove & replace the radiator cap to relieve any pressure.
2) disconnect the hoses from the heater core nipples, near the R hood hinge, and position them up so they don't drain.
3) remove the glove box.
- '80-86: remove 5 phillips screws and pull the box out;
- '87-96: fold the glove box down & remove it from its hinge;
- '87-96 F-series: remove the RABS module for access.
4) remove ~7 hex-head screws from the heater core cover, and remove the cover.
5) being careful not to damage the foam seal, remove the heater core.

Heater Hose Routing:
. .

See also:
How the cooling system works
. . . . .

Owner caption October 2010 · Photo 3393 of 6546