Heater Core: Service and Repair

Fig. 4 Typical plenum assembly removal. 1982---88:

Fig. 5 Typical heater core removal. 1982---88:

1982---88

1. Disconnect battery ground cable, then drain cooling system.

2. Disconnect heater hoses from heater core. Plug heater hoses and core fittings to prevent coolant spillage.

3. Remove bolt located below windshield wiper motor, attaching left end of plenum to dash panel.

4. Remove nut attaching upper lefthand corner of evaporator or heater case to dash panel.

5. Disconnect vacuum control system supply hose from vacuum source, then push grommet and hose into passenger compartment.

6. Remove glove box, then loosen right-hand door sill plate and remove side cowl trim panel.

7. Remove bolt attaching right-hand side of instrument panel to side cowl.

8. Remove instrument panel pad as follows:
a. Remove two screws from each defroster nozzle opening in pad.
b. From front lower edge of panel pad, remove five attaching screws.
c. From each end of pad, remove one attaching screw.
d. Lift pad assembly from instrument panel.

9. On models less ATC, disconnect temperature control cable from plenum bracket and blend air door crank.

10. On models equipped with ATC, disconnect temperature control cable and vacuum harness connector from ATC sensor. Disconnect ATC sensor tube from sensor and evaporator case connector, then disconnect wire connector from EVE relay.

11. On all models, remove push clip attaching center duct bracket to plenum, then rotate bracket upward and to the right.

12. Disconnect vacuum harness at vacuum connector near floor air distribution duct.

13. Disconnect the white vacuum hose from the outside recirculating air door vacuum motor.

14. Remove two screws from rear side of floor air distribution duct to plenum, Fig. 4. To remove the right-hand screw, it may be necessary to remove the two screws attaching the lower panel door vacuum motor to the mounting bracket.

15. Remove push fastener attaching floor air distribution duct to left end of plenum, then remove floor air distribution duct.

16. Remove two nuts located along lower flange of plenum.

17. Carefully move plenum rearward, so that heater core tubes and plenum case upper stud clear openings in dash panel, then remove plenum from vehicle by rotating upper portion of the plenum forward, down and out from under instrument panel. It may be necessary to carefully pull the lower edge of the instrument panel rearward while the plenum is being removed from behind the instrument panel.

18. Remove retaining screws from heater core cover, then the cover from the plenum assembly, Fig. 5.

19. Remove retaining screw from heater core inlet and outlet tube bracket.

20. Pull heater core and seal assembly from plenum assembly.

21. Reverse procedure to install.