Coolant Heater Replacement 4.3 L Engine

1. Drain the cooling system. Refer to Cooling System Draining and Filling .



2. Remove the heater cord from the engine coolant heater (4).
3. Loosen the bolt retaining the engine coolant heater to the block.
4. Remove the engine coolant heater from the engine block.
5. Do not score the machined surface of the hole.
6. Grasp the plug with pliers.
7. Pull the plug from the engine block.
8. 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 9985164 or the equivalent.

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

2. Tightly push the coolant heater (1) 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.




3. 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




4. Install the heater cord to the coolant heater (4).
5. Route the heater cord.
6. Fill the cooling system. Refer to Cooling System Draining and Filling .
7. Inspect the cooling system for leaks.

Coolant Heater Replacement 4.8 L, 5.3 L, and 6.0 L Engines

1. Drain the cooling system. Refer to Cooling System Draining and Filling .
2. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
3. Disconnect the coolant heater electrical connector (2).




Important: Do not score the surface of the engine block hole when removing the coolant heater.

4. Remove the coolant heater from the engine block.
5. Remove any burrs, sealer, paint or other rough spots.

1. If re-using the old coolant heater, apply thread sealant GM P/N United States 12346004, GM P/N Canada 10953480, or equivalent to the threads.

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 to the engine block.

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





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.

3. Connect the coolant heater electrical connector (2).
4. Lower the vehicle.
5. Fill the cooling system. Refer to Cooling System Draining and Filling .

Coolant Heater Replacement 8.1L Engine

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



3. Remove the engine block heater.

1. Apply sealant GM P/N 12346004, Canadian P/N 10953480 or equivalent to the threads of the engine block heater.

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 engine block heater into the block.

Tighten
Tighten the engine block heater to 60 N·m (40 lb ft).





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.

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

Coolant Heater Replacement 6.6 L 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. Remove the right front tire and wheel. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
4. Remove the right front fender wheelhouse inner fender (1).
5. Remove the right engine mount. Refer to Engine Mount Replacement - Right Side in Engine Mechanical - 6.6 L.



6. Disconnect the engine coolant heater cord.



7. Loosen the bolt retaining the engine coolant heater to the block.
8. Remove the engine coolant heater from the engine block.
9. Do not score the machined surface of the hole.
10. Grasp the plug with pliers.
11. Pull the plug from the engine block.
12. 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 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. Install the right engine mount. Refer to Engine Mount Replacement - Right Side in Engine Mechanical - 6.6 L.



8. Install the right front fender wheelhouse inner fender (1).
9. Install the right front tire and wheel. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
10. Lower the vehicle.
11. Fill the cooling system. Refer to Cooling System Draining and Filling .
12. Inspect for coolant leaks.