Heater Core: Service and Repair
Heating And Air Conditioning Assembly:
HEATER UNIT / CORE
Removal Procedure
Front Unit
1. Drain cooling system, disconnect heater hoses, then plug hoses and core tubes.
2. Remove instrument panel and evaporator case assembly, if equipped, refer to EVAPORATOR CORE AND EXPANSION VALVE.
3. On models with A/C, disconnect evaporator to compressor and receiver tank flare nuts.
4. Remove vacuum hose, then the evaporator relay connectors.
5. Remove evaporator nuts, then the evaporator unit assembly.
6. On models less A/C, remove connecting duct between heater and blower housings.
7. On all models, remove heater hoses, then disconnect and remove air ducts.
8. Disconnect electrical connectors from heater relay.
9. Remove heater case mounting nuts, and the heater assembly.
10. Remove defroster door spring, rod and lever.
11. Remove heater relay and blower resistor.
12. Remove core tube seal and support plate.
13. Remove water valve control valve, then withdraw core assembly from housing.
14. Reverse procedure to install.
Rear Unit
1. Disconnect battery ground cable and drain cooling system.
2. Remove rear seat, then disconnect heater hoses from rear heater assembly.
3. Remove heater assembly attaching bolts, disconnect blower motor electrical connector, then remove rear heater assembly from vehicle.
4. Remove clamps and remaining heater hoses.
5. Disconnect blower resistor wiring harness, then remove attaching screw and resistor.
6. Remove seal, then the left and right support brackets.
7. Remove attaching screws and front duct assembly.
8. Remove case retaining clips, separate case, then remove heater core.
9. Reverse procedure to install.
Heating And Air Conditioning Assembly:
Heater unit assembly
- Water valve link rod adjustment
(1) Set the air mix door to the stop position in a counter-clock- wise direction (cold position).
(2) Move the water valve lever to the stop position in a clockwise direction (cold position).
(3) Secure the link rod to the swivel joint with the screw.
- Mode and temp cable
(1) Attach the control assembly to the instrument panel using screws.
(2) Connect the cable, with the mode selector lever and heater assembly lever set in the OFF position. Secure the outer tube with cable clip.
(3) Connect the cable with the temperature lever and heater lever set in the HOT position, then fix the outer tube with a cable clip. Check all doors and the water valve. If the doors or the valve are not closing properly, loosen the cable clamp screw at the control and adjust the cable length as required.
- Defroster door - The defroster door should be in the defroster position when the control lever is moved to the DEF and HEAT positions. Air is directed to the defroster outlets.
- Heat door - In the positions of HEAT and BI-LEVEL, air is directed to the floor outlets. Air is not delivered to other outlets. However, when the heater is in use, some air is directed to the defroster.
- Vent door - In the positions of VENT and BI-LEVEL, air is directed out the center and side outlets. Air is not delivered to any other outlets.
- Air mix door - When the temperature control lever is in the HOT position, hot air is delivered and the water valve is opened fully. In COLD position, non-heated air is delivered and the water valve is completely closed.
Flare nuts ; evaporator to compressor and receiver tank
Note: * Control levers