GM Service Manual Online
For 1990-2009 cars only

Coolant Heater Replacement Dealer Installation - 6.0L Engine

Dealer Installation Only


    Object Number: 309158  Size: SH
  1. Drain the cooling system/engine block. 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. Remove the oil pan skid plate bolts and plate.

  4. Object Number: 846669  Size: SH
  5. Remove the oil cooler hose bracket bolt.
  6. Remove the oil cooler hose adapter bolts.
  7. Remove and discard the oil cooler hose adapter gasket.
  8. Position the oil cooler hose adapter end out of the way.

  9. Object Number: 786910  Size: SH

    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.

  10. Install the coolant heater in place of the drain plug.
  11. Tighten
    Tighten the coolant heater to 50 N·m (37 lb ft).


    Object Number: 661139  Size: SH
  12. Push the engine coolant heater cord electrical connector (2) firmly into the coolant heater (1).
  13. Important: The engine coolant heater cord must not touch the engine, hot pipes, manifold, or any moving parts. Always keep the electrical cord neatly rolled up with the end of the cord tucked in the center of the coil and secured in place.


    Object Number: 661277  Size: SH
  14. Place the cord into position.
  15. Install the heater cord bolt and retainer.
  16. Tighten
    Tighten the bolt to 8 N·m (71 lb in).


    Object Number: 846669  Size: SH
  17. Position the oil cooler hose adapter.
  18. Install a NEW oil cooler hose adapter gasket.
  19. Install the oil cooler hose adapter bolts.
  20. Tighten
    Tighten the bolts to 12 N·m (106 lb in).

  21. Install the oil cooler hose bracket bolt.
  22. Tighten
    Tighten the bolt to 25 N·m (18 lb ft).


    Object Number: 309158  Size: SH
  23. Install the oil pan skid plate and bolts.
  24. Tighten
    Tighten the bolts to 20 N·m (15 lb ft).

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

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

Removal Procedure


    Object Number: 309158  Size: SH
  1. Drain the cooling system/engine block. 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. Remove the oil pan skid plate bolts and plate.

  4. Object Number: 846669  Size: SH
  5. Remove the oil cooler hose bracket bolt.
  6. Remove the oil cooler hose adapter bolts.
  7. Remove and discard the oil cooler hose adapter gasket.
  8. Position the oil cooler hose adapter end out of the way.

  9. Object Number: 661139  Size: SH
  10. Disconnect the coolant heater electrical connector (2).

  11. Object Number: 661276  Size: SH

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

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

Installation Procedure


    Object Number: 661276  Size: SH
  1. If reusing the old coolant heater, apply thread sealant GM P/N 12346004 (Canadian P/N 10953480), or equivalent to the threads.
  2. 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. Install the coolant heater to the engine block.
  4. Tighten
    Tighten the coolant heater to 50 N·m (37 lb ft).


    Object Number: 661139  Size: SH
  5. Connect the coolant heater electrical connector (2).

  6. Object Number: 846669  Size: SH
  7. Position the oil cooler hose adapter end.
  8. Install a NEW oil cooler hose adapter gasket.
  9. Install the oil cooler hose adapter bolts.
  10. Tighten
    Tighten the bolts to 12 N·m (106 lb in).

  11. Install the oil cooler hose bracket bolt.
  12. Tighten
    Tighten the bolt to 25 N·m (18 lb ft).


    Object Number: 309158  Size: SH
  13. Install the oil pan skid plate and bolts.
  14. Tighten
    Tighten the bolts to 20 N·m (15 lb ft).

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

Coolant Heater Replacement 8.1L

Removal Procedure


    Object Number: 309158  Size: SH
  1. Drain the cooling system/engine block. 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. Remove the oil pan skid plate bolts and plate.

  4. Object Number: 751506  Size: SH
  5. Disconnect the coolant heater electrical connector.

  6. Object Number: 635660  Size: SH
  7. Remove the coolant heater from the engine block.

Installation Procedure


    Object Number: 635660  Size: SH
  1. If reusing the old coolant heater, apply sealant GM P/N 12346004, (Canadian P/N 10953480), or equivalent to the threads.
  2. 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. Install the coolant heater into the engine block.
  4. Tighten
    Tighten the coolant heater to 60 N·m (40 lb ft).


    Object Number: 751506  Size: SH

    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 coolant heater electrical connector.
  6. Fill the cooling system/engine block. Refer to Cooling System Draining and Filling .

Coolant Heater Replacement 5.3L (w/RPO L33)

Removal Procedure

  1. Remove the engine protection shield. Refer to Engine Protection Shield Replacement .
  2. Remove the front drive axle shield. Refer to Shield Replacement .
  3. Drain the cooling system. Refer to Cooling System Draining and Filling .
  4. Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle .

  5. Object Number: 673597  Size: SH
  6. Disconnect the coolant heater electrical connector.
  7. Important: Do not score the surface of the engine block hole when removing the coolant heater.

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

Installation Procedure

  1. If reusing the old coolant heater, apply thread sealant to the to the threads. Refer to Adhesives, Fluids, Lubricants, and Sealers for the correct part number.
  2. Notice: Refer to Fastener Notice in the Preface section.

  3. Install the coolant heater to the engine block.
  4. Tighten
    Tighten the coolant heater to 50 N·m (37 lb ft).


    Object Number: 673597  Size: SH

    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 coolant heater electrical connector.
  6. Lower the vehicle.
  7. Fill the cooling system. Refer to Cooling System Draining and Filling .
  8. Install the front drive axle shield. Refer to Shield Replacement .
  9. Install the engine protection shield. Refer to Engine Protection Shield Replacement .