Coolant Heater Replacement With LC9, 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.




Important: 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 equipped, install the oil cooler hose adapter bolts (2) And tighten to 12 N·m (106 lb in).
8. If equipped, install the oil cooler hose bracket bolt (1) and tighten to 25 N·m (18 lb ft).



9. If equipped, 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 With LY2, LMG, LY5, LY6 or LFA

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.




Important: 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 equipped, 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 equipped, 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.