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.

Coolant Heater Replacement 6.6L (LLY) Engine

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



4. Loosen the coolant heater bolt.
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: Refer to Fastener Notice in the Preface section.




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 to 2 N·m (18 lb in).





Notice: 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 heater cord to the coolant heater.
6. Install the ground wire to engine block.
7. Fill the cooling system. Refer to Cooling System Draining and Filling .
8. Inspect for coolant leaks.

Coolant Heater Replacement LF8

1. Drain the coolant. Refer to Cooling System Draining and Filling .
2. Remove the shield, if equipped.



3. Remove the electrical cable from the engine coolant heater.



4. Remove the heater from the engine block.
5. Inspect the holes in the block for smoothness. Remove any burrs or rough spots.
6. Inspect the electrical cable connectors for the following conditions:

•

Corrosion

•

Damage

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

7. Inspect the following components for damage:

•	The electrical cable

•

The plug

8. Clean the following components:

•	The hole in the block

•	The electrical connectors

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

•	The opening of the engine block

•	The rubber O-ring seal on the heater




2. Insert the engine coolant heater into the hole in the engine block.

Notice: Refer to Fastener Notice in the Preface section.




3. Position the engine coolant heater hairpin end toward the front of the vehicle.

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

4. Install the shield, if equipped.




Important: Leave slack in the electrical cable between the engine and the frame. This will ensure that engine vibration will not stretch the cable or damage the connection.

5. Connect the electrical cable to the engine coolant heater.

Ensure that the cable does not touch the following components:

•	The engine

•	The manifold

•	Any moving parts

6. Fill the cooling system. Refer to Cooling System Draining and Filling .
7. Inspect the system for leaks.