Coolant Heater Replacement 6.6L Engine

1. Drain the cooling system and the engine block. Refer to Cooling System Draining and Filling .
2. Raise the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.



3. Disconnect the engine coolant heater cord.



4. Loosen the bolt retaining the engine coolant heater to the block.
5. Remove the engine coolant heater from the engine block.
6. Do not score the machined surface of the hole.
7. Grasp the plug with pliers.
8. Pull the plug from the engine block.
9. Clean the core plug hole in order to remove the following substances:

•

Burrs

•

Compound

•

Paint

•	Rough spots

1. Coat the O-ring seal and the cleaned surface of the plug opening with water resistant high-temperature grease lubricant GM P/N 1052196 (Canadian P/N 5264008) or the equivalent.

Important: Avoid element contact with the inside walls of the engine block.

2. Align the coolant heater element to point towards the top of the engine.
3. Tightly push the coolant heater into the engine block.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.




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

Tighten
Tighten the bolt in order to retain the engine coolant heater to the engine block to 2 N·m (18 lb in).

Important: Do not allow the heater cord to touch the following areas:

•	The engine

•

Hot pipes

•	The manifold

•	Any moving parts




5. Install the heater cord to the coolant heater.
6. Route the heater cord.
7. Lower the vehicle.
8. Fill the cooling system. Refer to Cooling System Draining and Filling .
9. Inspect for coolant leaks.

Coolant Heater Replacement L18

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

1. Coat the O-ring seal and the cleaned surface of the plug opening with water resistant high-temperature grease lubricant GM P/N 12346004 (Canadian P/N 10953480) or the equivalent.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

2. Install the coolant heater.

Tighten
Tighten the engine coolant heater to 50 N·m (40 lb ft).

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

Coolant Heater Replacement LG5

1. Drain the coolant. Refer to Cooling System Draining and Filling .
2. Remove the heat shield, if equipped.
3. Disconnect the electrical cord connector from the engine coolant heater.
4. Loosen the center screw to the limit of the thread.



5. Remove the engine coolant heater from the engine block.
6. Inspect the hole in the block for smoothness. Remove any burrs or rough spots.

Caution: A block heater electrical cord that is damaged creates a shock hazard, and must be replaced.

7. Inspect the electrical cord and the cord ends for corrosion or damage.
8. Clean the hole in the block.
9. Clean the electrical connectors.

1. Apply a coat of petroleum jelly to the following components:

•	The opening of the heater

•	The rubber O-ring seal




2. Insert the engine coolant heater into the hole in the engine block.
3. Position the hairpin end of the engine coolant heater straight up.

Notice: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems.

4. Tighten the engine coolant heater center screw.

Tighten
Tighten the engine coolant heater center screw to 3 N·m (23 lb in).

5. Install the heat shield, if equipped.

Tighten
Tighten the heat shield bolt to 12 N·m (106 lb in).

Important: Route the electrical cord so that the cord does not touch the engine, the exhaust manifold or any moving parts. Leave slack between the engine and the frame so that engine vibration will not stretch the cord or damage the connection at the heater.

6. Connect the electrical cord connector to the engine coolant heater.
7. Fill the cooling system. Refer to Cooling System Draining and Filling .
8. Inspect the system for leaks.