GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 GMC_Truck 🢒 2010 🢒 Sierra - 4WD 🢒 Engine 🢒 Engine Cooling 🢒 Coolant Heater Replacement

Coolant Heater Replacement LU3

Removal Procedure

    Object Number: 312949 Size: SH
  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:
    9. • Burrs
    • Compound
    • Paint
    • Rough spots

Installation Procedure

    Object Number: 312935 Size: SH
  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.

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

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

    3. Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 312945 Size: SH
  3. Tighten the coolant heater bolt until both of the locking wings draw tightly against the inner wall of the engine block.

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


    Object Number: 312949 Size: SH

    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

Removal Procedure

    Object Number: 674570 Size: SH
  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. Object Number: 663089 Size: SH
  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:
    11. • Burrs
    • Compound
    • Paint
    • Rough spots

Installation Procedure

    Object Number: 663089 Size: SH
  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.

    2. 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.

    4. Caution: Refer to Fastener Caution in the Preface section.


    Object Number: 312945 Size: SH
  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.

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


    Object Number: 674570 Size: SH

    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.