Coolant Heater Replacement 3.8L Engine

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



4. Loosen the coolant heater bolt.

Important: When removing the engine coolant heater from the engine block, be careful not to score the machined surface of the plug hole.

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

Important: The heater element must not touch the engine block inner wall in the installed position or damage to the engine block and coolant heater could result.

1. Apply a coat of engine coolant heater lubricant, GM P/N 12345996 or equivalent, to the O-ring and walls of the coolant heater hole.




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 into the coolant hole using the following steps:

•	Insert the heating element end of the heater into the engine block.

•	Line up the heater with the plug hole and push it straight into place.

•	Rotate the heater so that the center electrical contact and bolt are in line horizontally.

•	Tighten the bolt so that the yoke presses against the engine block inner wall.

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




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

Coolant Heater Replacement 5.7L Engine

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

Important: When removing the engine coolant heater from the engine block, be careful not to score the machined surface of the plug hole.




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

Important: The heater element must not touch the engine block inner wall in the installed position or damage to the engine block and coolant heater could result.

1. Apply a coat of engine coolant heater lubricant, GM P/N 12345996 or equivalent, to the O-ring and walls of the coolant heater hole.



2. Finger start the coolant heater to 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 coolant heater.

Tighten
Tighten the coolant heater to 40 N·m (30 lb ft).




4. Install the coolant heater electrical cord to the heater.
5. Lower the vehicle.
6. Fill the cooling system. Refer to Cooling System Draining and Filling .