Coolant Heater Replacement 4.3L

1. Drain the cooling system. Refer to Cooling System Draining and Filling .
2. Disconnect the heater cord from the coolant heater (4).
3. Loosen the coolant heater bolt.
4. Remove the 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 (Canadian P/N 10953480), 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 coolant heater bolt 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.

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

Coolant Heater Replacement 4.8L/5.3L (except RPO L33) 6.0L

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 .
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 12346004 (Canadian P/N 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 6.6L

1. Drain the cooling system. Refer to Cooling System Draining and Filling .
2. Remove the right front tire and wheel. Refer to Tire and Wheel Removal and Installation .
3. Disconnect the engine coolant heater cord.



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 right front tire and wheel. Refer to Tire and Wheel Removal and Installation .
7. Fill the cooling system. Refer to Cooling System Draining and Filling .
8. Inspect for coolant leaks.

Coolant Heater Replacement 4.8L/5.3L/6.0L

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



3. For vehicles with regular production option (RPO) L76 (6.0L), perform the following steps. Otherwise, proceed to step 8.
4. Remove the oil cooler hose bracket bolt (1), if equipped.
5. Remove the oil cooler hose adapter bolts (2), if equipped.
6. Remove and discard the oil cooler hose adapter gasket, if equipped.
7. Position the oil cooler hose adapter end out of the way, if equipped.



8. Disconnect the coolant heater cord electrical connector (1).




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

9. Remove the coolant heater from the engine block.
10. Remove any burrs, sealer, or other rough spots.

1. If reusing the old coolant heater, apply thread sealant GM P/N 12346004 (Canadian P/N 10953480), or equivalent to the threads.

Notice: Refer to Fastener Notice in the Preface section.

2. Install the coolant heater to the engine block.

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




3. Connect the coolant heater cord electrical connector (1).



4. For vehicles with RPO L76 (6.0L) perform the following steps otherwise proceed to step 10.
5. Position the oil cooler hose adapter end, if equipped.
6. Install a NEW oil cooler hose adapter gasket, if equipped.
7. Install the oil cooler hose adapter bolts (2), if equipped.

Tighten
Tighten the bolts to 12 N·m (106 lb in).

8. Install the oil cooler hose bracket bolt (1), if equipped.

Tighten
Tighten the bolt to 25 N·m (18 lb ft).

9. Lower the vehicle.
10. Fill the cooling system/engine block. Refer to Cooling System Draining and Filling .