Heater core — replacement
Warning: The models covered by this manual are equipped with a Supplemental Restraint System (SRS), more commonly known as airbags. Always disable the airbag system before working in the vicinity of any airbag system components to avoid the possibility of accidental deployment of the airbag, which could cause personal injury (see Chassis electrical system).
Warning: Do not allow antifreeze to come in contact with your skin or painted surfaces of the vehicle. Rinse off spills immediately with plenty of water. Antifreeze is highly toxic if ingested. Never leave antifreeze lying around in an open container or in puddles on the floor; children and pets are attracted by its sweet smell and may drink it. Check with local authorities about disposing of used antifreeze. Many communities have collection centers which will see that antifreeze is disposed of safely. Never dump used antifreeze on the ground or into drains.
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 should be properly discharged into an EPA-approved container at a dealer service department or an automotive air conditioning repair facility. Always wear eye protection when disconnecting air conditioning system fittings.
Warning: Wait until the engine is completely cool before beginning this procedure.
Note: Replacement of the heater core is a difficult procedure for the home mechanic, involving removal of the entire dashboard, floor console and many wiring connectors. If you attempt this procedure at home, keep track of the assemblies by taking notes and keeping screws and other hardware in small, marked plastic bags for reassembly.
1. If the vehicle is equipped with air conditioning, have the air conditioning system discharged at a dealer service department or service station.
2. Turn the heater control setting to HOT. Drain the cooling system (see Tune-up and routine maintenance). If the coolant is relatively new, or is in good condition, save it and re-use it.
3. Disconnect the cable from the negative battery terminal (see Engine electrical systems).
4. Working in the engine compartment, disconnect the heater hoses from the heater core tubes at the firewall (see illustration).
i.4 Squeeze the clamps and disconnect the heater hoses at the firewall
5. Remove the rubber grommets where the heater core tubes go through the firewall.
6. Remove the air conditioning refrigerant lines manifold bolt to the expansion valve (see illustration), then remove the expansion valve mounting bolt and remove the valve from the evaporator core. Cap the open fittings immediately to keep moisture and dirt out of the system.
i.6 Air conditioning refrigerant lines manifold bolt-to-expansion valve location
Warning: Always wear eye protection when disconnecting air conditioning system fittings and always cap the fitting ends to prevent moisture from entering the refrigerant lines.
7. Remove the steering column (see Suspension and steering systems).
8. Remove the entire instrument panel (see Body).
9. Disconnect the electrical connectors from the blower motor and the blower resistor, then remove the blower unit.
10. Remove the rear floor duct, then remove the upper air duct mounting nuts and remove the duct.
11. Disengage the defroster duct clips and remove the defroster duct assembly.
12. Remove the vertical instrument panel brace fasteners and remove the two braces.
13. Remove the instrument panel reinforcement beam (see Body).
14. Remove the remaining air conditioning unit fasteners and remove the assembly from the vehicle.
15. Disconnect the wiring harness from the clips along the blower motor housing, then remove the blower motor housing-to-air conditioning unit fasteners and separate the two housings.
16. Remove the quick heater fasteners, then disconnect the electrical connectors and remove the quick heater from the air conditioning unit housing.
17. Detach the retaining clamp screw and remove the clamp, then remove the heater core from the air conditioning unit housing. Note: The heater core is located on the passenger’s side of the NC unit.
18. Reinstall the remaining parts in the reverse order of removal.
19. Refill the cooling system (see Tune-up and routine maintenance), reconnect the battery and run the engine. Check for leaks and proper operation of the system. Have the air conditioning system recharged if equipped.