Coolant Heater Replacement With LH6, LY2, LGM,LY5 or LY6

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 1500 series vehicles, remove the oil pan skid plate bolts and plate, if equipped.



4. For 2500 series vehicle, remove the front 2 oil pan skid plate bolts, loosen the 2 rear bolts and remove the skid plate, if equipped.



5. For vehicles with regular production option (RPO) LY6 (6.0L) perform the following steps otherwise proceed to step 10.
6. Remove the oil cooler hose bracket bolt (1).
7. Remove the oil cooler hose adapter bolts (2).
8. Remove and discard the oil cooler hose adapter gasket.
9. Reposition the oil cooler hose adapter end out of the way.



10. Disconnect the coolant heater cord electrical connector.




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

11. Remove the coolant heater from the engine block.
12. 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.

Caution: Refer to Fastener Caution in the Preface section.

2. Install the coolant heater to the engine block and tighten to 50 N·m (37 lb ft).



3. Connect the coolant heater cord electrical connector.



4. For vehicles with RPO LY6 (6.0L) perform the following steps otherwise proceed to step 9.
5. Position the oil cooler hose adapter end.
6. Install a NEW oil cooler hose adapter gasket.
7. Install the oil cooler hose adapter bolts (2) and tighten to 12 N·m (106 lb in).
8. Install the oil cooler hose bracket bolt (1) and tighten to 25 N·m (18 lb ft).



9. If applicable, for 2500 series vehicles, position the oil pan skid plate and install the 2 front bolts and tighten the 2 rear bolts and tighten to 20 N·m (15 lb ft).



10. If applicable, for 1500 series vehicles position and install the oil pan skid plate and bolts and tighten to 20 N·m (15 lb ft).
11. Lower the vehicle.
12. Fill the cooling system/engine block. Refer to Cooling System Draining and Filling.

Coolant Heater Replacement With L76 or L92

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. Remove the oil pan skid plate bolts and plate, if equipped.



4. For vehicles with regular production option (RPO) L76 (6.0L), perform the following steps. Otherwise, proceed to step 9.
5. Remove the oil cooler hose bracket bolt (1), if equipped.
6. Remove the oil cooler hose adapter bolts (2), if equipped.
7. Remove and discard the oil cooler hose adapter gasket, if equipped.
8. Position the oil cooler hose adapter end out of the way, if equipped.



9. Disconnect the coolant heater cord electrical connector.




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

10. Remove the coolant heater from the engine block.
11. 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.

Caution: Refer to Fastener Caution in the Preface section.

2. Install the coolant heater to the engine block and tighten to 50 N·m (37 lb ft).



3. Connect the coolant heater cord electrical connector.



4. For vehicles with RPO L76 (6.0L) perform the following steps otherwise proceed to step 9.
5. Position the oil cooler hose adapter end, if equipped.
6. Install a NEW oil cooler hose adapter gasket, if equipped.
7. If applicable, install the oil cooler hose adapter bolts (2) and tighten to 12 N·m (106 lb in).
8. If applicable, install the oil cooler hose bracket bolt (1) and tighten to 25 N·m (18 lb ft).



9. If applicable, position and install the oil pan skid plate and bolts and tighten to 20 N·m (15 lb ft).
10. Lower the vehicle.
11. Fill the cooling system/engine block. Refer to Cooling System Draining and Filling.

Coolant Heater Replacement LU3

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.

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

2. Tightly push the coolant heater (1) into the engine block.

Caution: Refer to Fastener Caution in the Preface section.




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

Tighten the bolt to 2 N·m (18 lb in).





Caution: 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 LMM

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. Remove the right engine mount. Refer to Engine Mount Replacement - Right Side.
4. Disconnect the engine coolant heater cord.



5. Loosen the coolant heater bolt.
6. Remove the engine coolant heater from the engine block.
7. Do not score the machined surface of the hole.
8. Grasp the plug with pliers.
9. Pull the plug from the engine block.
10. 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.

Note: 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.

Caution: Refer to Fastener Caution 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 the bolt to 2 N·m (18 lb in).





Caution: 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. Remove the right engine mount. Refer to Engine Mount Replacement - Right Side.
7. Install the right front tire and wheel. Refer to Tire and Wheel Removal and Installation.
8. Fill the cooling system. Refer to Cooling System Draining and Filling.
9. Inspect for coolant leaks.