Heater core — removal and installation
possibility of accidental deployment of the airbag, which could cause personal injury (see Chassis electrical system).
Warning: The air conditioning system is under high pressure. DO NOT loosen any fittings or remove any components until after the system has been discharged. Air conditioning refrigerant must be properly discharged into an EPA-approved container at a
dealership service department or an automotive air conditioning facility. Always wear eye protection when disconnecting air conditioning system fittings.
Warning: Wait until the engine is completely cool before beginning this procedure.
1. Have the air conditioning system discharged by a dealership service department or an automotive air conditioning facility (see the Warning above).
Front heater core
2. Disconnect the cable from the negative terminal of the battery (see Engine electrical systems).
3. Remove the battery and battery tray (see Engine electrical systems).
4. Drain the cooling system (see Tune-up and routine maintenance). Detach the air conditioning lines from the evaporator core fittings at the firewall (see illustration 17.2). Be sure to plug each refrigerant line to avoid contamination of the air conditioning system.
5. Disconnect the heater hoses from the heater core pipes on the engine side of the firewall (see illustration). Plug the open fittings.
12.5 Disconnect the heater core hoses at the engine compartment firewall using a special offset disconnect tool. After the special disconnect tool is slid into the spring lock mechanism, pull the heater core hose back and off the heater core pipe
6. Remove the intake manifold (see V6 engine or 2B).
7. Remove the dash and dash carriage (see Body).
8. Disconnect the drain tube at the firewall (see illustration 3.1).
9. Support the heating/air conditioning unit with a block of wood inside the vehicle (see illustration).
12.9 Support the heating/air conditioning unit with a block of wood to prevent it from falling once the mounting bolt/nuts are removed
10. Working in the engine compartment, remove the fasteners securing the heating/air conditioning unit to the firewall (see illustrations).
12.10a Heater/air conditioning unit mounting bolt/nut locations — right s ide (passenger’s side) of engine compartment
12.10b Heater/air conditioning unit mounting bolt/nut locations — center of engine compartment
11. Working back inside the passenger compartment, remove the electrical connectors and any ground straps, then remove the heating/air conditioning unit from the vehicle.
12. Remove the temperature valve actuator screws (see illustration) and lift the actuator off of the case.
12.12 Temperature valve actuator details;
1 Electrical connector
2 Mounting screws
13. The heater core/evaporator core cover has melted plastic stakes where the mounting screws would normally be installed. To remove the melted stakes, use a drill bit and carefully cut the heads of the plastic stakes off (see illustrations).
12.13a Locate the plastic stakes (rivets) around the perimeter of the cover …
12.13b … then use a drill to cut the head of the stake off without drilling into the cover
14. Disconnect the control module harness connectors, then depress the tabs and remove the blower motor control module (see illustration).
12.14 Release the tabs and lift the control module off of the housing
15. Remove the heater core cover (see illustration).
12.15 The heater core cover is at the top of the heater/air conditioning unit
16. Carefully lift the heater core out of the housing (see illustration).
12.16 Remove the heater core from the housing
17. Installation is the reverse of removal.
Note: When reinstalling the heater core, make sure any original insulating/sealing materials are in place around the heater core pipes, heater core and heating/air conditioning unit.
18. Refill the cooling system (see Tune-up and routine maintenance). Have the air conditioning system charged by the shop that discharged it.
19. Start the engine and check for proper operation and leaks.
Rear (auxiliary) heater core
20. Remove the right rear quarter trim panel (see Body).
21. Detach the air conditioning lines from the rear evaporator core fittings on the underside of the vehicle. Be sure to plug each refrigerant line to avoid contamination of the air conditioning system. Use special release tools to remove the quick-connect fittings.
22. Also working from the underside of the vehicle, clamp off the heater hoses leading to the rear heater core, then disconnect the hoses from the inlet and outlet fittings and plug the open fittings. To disconnect the hose fittings, squeeze the plastic retainer tabs, then pull off the hoses.
23. Remove the upper auxiliary air duct.
24. Remove the rear heating/air conditioning unit lower mounting nuts from under the vehicle.
25. Remove the electrical connectors and wiring harness retaining straps, then unscrew the rear heating/air conditioning unit mounting upper screws and remove the housing from the vehicle. Follow the remaining steps to remove the heater core from the rear heating/ air conditioning unit.
26. On long wheel base models, remove the heater core cover located on the bottom of the heater/air conditioning unit.
27. On short wheel base models, remove the blower/heater core case mounting screws and separate the two case halves.
28. Remove the heater core from the housing.
29. Installation is the reverse of removal.
Note: When reinstalling the heater core, make sure any original insulating/sealing materials are in place around the heater core pipes, heater core and housing.
30. Check the coolant level, adding coolant as necessary (see Tune-up and routine maintenance).