Coolant Heater Replacement 3.5L

1. Drain the cooling system. Refer to Cooling System Draining and Filling.
2. Disconnect the coolant heater cord from the coolant heater.
3. Loosen the bolt at the coolant heater but do not remove.
4. Remove the coolant heater.
5. Remove and clean any burrs, compound, paint, or rough spots from the core plug hole.

1. Apply a coat of GM  P/N 12346004, (Canadian P/N 10953480) thread sealant with Teflon or equivalent to the O-ring and clean the surface of the plug opening.
2. Install the coolant heater by pushing tight to the block.



3. Install the coolant heater so the element is at the 9 o'clock position (2).

Caution: Refer to Fastener Caution in the Preface section.

4. Tighten the coolant heater bolt until both locking wings draw tight against the inner wall of the engine block.

Tighten
Tighten the bolt to 2 N·m (17 lb in).

Caution: The heater cord must not touch the engine, hot pipes, manifold, or any moving parts. Route the cord to the left front of the engine compartment securing with tie straps as necessary to prevent damage.

5. Connect the coolant heater cord to the coolant heater.
6. Fill the cooling system. Refer to Cooling System Draining and Filling.

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.

Caution: Refer to Fastener Caution 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.