Heater Core: Service and Repair

1. Disconnect battery ground cable, place temperature control lever in HOT position, drain cooling system.
2. On models with A/C, discharge A/C system using refrigerant recovery equipment, disconnect refrigerant lines to evaporator, then plug lines and open fittings.





3. Remove passenger side instrument lower cover and glove compartment.
4. Disconnect control cable or vacuum lines at air intake door control, and disconnect wiring harness connector to blower motor.

Fig. 12 Exploded View Of Heater System. 89 300zx:

5. Remove bolts securing air intake and blower housing, then remove housing assembly.
6. On models with A/C, remove evaporator case.
7. Disconnect heater hoses at water valve inlet and heater core outlet, taking care not to drip coolant in passenger compartment.
9. Remove bolts securing heater case, then remove heater assembly.





8. Separate case halves and remove heater core.
9. Reverse procedure to install.