Coolant Heater Replacement LS4

1. Drain the cooling system. Refer to Cooling System Draining and Filling .
2. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .
3. Disconnect the coolant heater cord from the coolant heater.
4. Remove the coolant heater (114) and washer (115).
5. Remove and clean any burrs, compound, paint, or rough spots from the core plug hole.

1. Apply a 3.175 mm (0.125 in) bead of sealant, GM P/N 12346004 (Canadian P/N 10953480) or equivalent to the coolant heater.

Notice: Refer to Fastener Notice in the Preface section.

2. Install the coolant heater (114) and washer (115).

Tighten
Tighten the coolant heater to 50 N·m (37 lb ft).

3. Connect the coolant heater cord to the coolant heater.
4. Lower the vehicle.
5. Fill the cooling system. Refer to Cooling System Draining and Filling .

Coolant Heater Replacement RPOs LZE/LZ4/LZ9

1. Drain the cooling system. Refer to Cooling System Draining and Filling .
2. Disconnect the engine coolant heater cord (2) from the engine coolant heater.



3. Remove the engine coolant heater.
4. Clean the engine coolant heater opening.

Notice: Refer to Fastener Notice in the Preface section.




1. Apply sealer GM P/N 12346004 (Canadian P/N 10953480) or equivalent to the threads of the engine coolant heater, if necessary.
2. Install the engine coolant heater.

Tighten
Tighten the coolant heater to 60 N·m (44 lb ft).




3. Connect the engine coolant heater cord (2) to the engine coolant heater.
4. Lower the vehicle.
5. Fill the cooling system. Refer to Cooling System Draining and Filling .
6. Inspect for leaks.