Heater Core: Service and Repair

Heater Core Replacement

Removal Procedure

1. Disconnect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection.
2. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
3. Drain the coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
4. Lower the vehicle.






5. Remove the heater inlet hose:
- From the auxiliary water pump outlet on L81 engines.
- From the thermostat outlet on L61 engines.






6. Remove the heater outlet hose:
- From the head bridge on L81 engines.
- From the block inlet on L61 engines.
7. Place the end of heater outlet hose in a container and apply low pressure 34 kPa (5 psi) shop air to the heater inlet hose to blow the coolant out of the heater core.






8. Remove the right console extension.

Caution: Avoid contact with moving parts and hot surfaces while working around a running engine in order to prevent physical injury.






9. Remove the heater core pipe to heater core clamps.
- The clamps may need to be rotated to gain access to the clamp retaining tab.
10. Gently pull the pipes forward to remove the pipes from the heater core end tank.
11. Place absorbent rags under the heater core pipe joints to catch any residual coolant.






12. Remove the heater core retaining strap screw.
13. Remove the heater core retaining strap.

Important: Use care not to spill any residual coolant on carpet or seats.

Important: The center console forward edge may need to be pulled outward to allow for the core to be removed.

14. Remove the heater core from the HVAC module.

Installation Procedure






1. Install the heater core into the HVAC module being careful not to damage the foam seals.
2. Install the heater core retaining strap.
3. Install the heater core retaining strap screw. Tighten the screw to 1.9 Nm (9 lb in).






4. Install the bushings and O-rings onto the heater core pipes.
5. Install the heater pipes into the core and install the plastic clamps.
- The heater pipe clamps will only go on one way.
- The lower clamp hinge fits into the tab of the heater core retaining strap.






6. Install the right console extension.






7. Install the heater inlet hose to:
- The auxiliary water pump outlet on L81.
- The thermostat outlet on L61.
8. Install the clamp at the 12 o'clock position.






9. Install the heater outlet hose to:
- The block inlet on L61.
- Install the clamp at the 12 o'clock position.
- Install the head bridge on L81.
- Install the clamp at the 3 o'clock position.
10. Connect the negative battery cable. Refer to Battery Negative Cable Disconnection and Connection.
11. Fill the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.
12. Rinse off any coolant that was spilled in the engine compartment.