Heater Core Removal and Installation For 1973-1979 Ford F-Series Trucks

By Thomas Hogan


  1. Disconnect the battery ground cable.
  2. Remove the air cleaner.
  3. Drain the engine coolant below the level of the
    heater core.
  4. Remove the heater hoses from the heater core.
  5. Remove the screw fastening the A/C hose support
    bracket to the firewall.
  6. The expansion valve is located on the right side
    of the evaporator core housing. Remove the insulating tape covering
    the valve.
  7. Remove the two screws holding the plate over
    the opening that the A/C hoses exit the evaporator housing. Remove
    the plate and the seal.
  8. Remove the glove box liner.
  9. Separate the A/C duct from the register in the
    instrument panel and free the clip holding it to the plenum.
    Remove the duct from under the dash.
  10. Remove the vacuum hose from the vacuum motor
    on the right hand side of the air box.
  11. Remove the rear housing cover from the evaporator
    housing. The cover is retained by 4 nuts and one bolt. Disconnect
    the fresh air tube from the rear cover. After the cover is removed
    reinstall one nut to secure the evaporator housing to the firewall.
  12. Gently remove the capillary tube from the evaporator
    core. Disconnect the wires from the icing sensor. Remove the
    plate the sensor is mounted to.
  13. Remove the plenum by extracting the two screws
    above the transmission tunnel that hold the plenum to the dash.
  14. Remove the screws securing the evaporator.
  15. Pull the evaporator from the case and secure
    it above the case.
  16. Remove the heater core.
  17. Remove the heater air control door. There are
    no screws this is retained by a spring clip and snaps off.
  18. Remove the arm that supports the air control
    door and the retainer that secures the pivot arm.
  19. Remove the blower motor.
  20. Transfer the blower wheel to the new motor.
  21. Reverse the disassembly steps to assemble the
    heater A/C box.

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