GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

  1. Drain the engine coolant. Refer to Cooling System Draining and Filling .
  2. If not originally equipped with an engine coolant heater, remove the coolant jacket plug by using the following procedure:
  3. 2.1. Carefully tap the coolant jacket plug near the outer edge. This causes the plug to rotate in the hole.

    Do not score the machined surface of the hole.

    2.2. Grasp the plug with pliers and pull the plug out.

    Object Number: 341092  Size: MH
  4. Remove the cord from the engine coolant heater.
  5. Loosen the bolt.
  6. Remove the engine coolant heater.
  7. Clean the core plug hole. Remove any of the following conditions:
  8. • Burrs
    • Compound
    • Paint
    • Rough spots

Installation Procedure

  1. Apply a coating of lubricant to the O-ring seal and the cleaned surface of the plug opening in the block. Use a water spray resistant, high-temperature grease lubricant (GM P/N 9985164 or equivalent).
  2. Notice: The block heater element must not touch the engine block inner wall in the installed position or damage to the engine block and the block heater could result.


    Object Number: 341276  Size: SH
  3. Install the engine block heater into the engine block. Position the heater element 90 degrees perpendicular (1) to the crankshaft centerline.

  4. Object Number: 300797  Size: SH
  5. Push the engine coolant heater into the block until the outer edge is flush with the engine block surface.

  6. Object Number: 300799  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.

  7. Tighten the bolt until both locking wings draw tight against the inner wall of the engine block.
  8. Tighten
    Tighten the bolt to 1.9 N·m (17 lb in).


    Object Number: 341092  Size: MH

    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.

  9. Install the heater cord to the coolant heater. Route and secure the heater cord through the engine as shown.

  10. Object Number: 341097  Size: SH
  11. Route and secure the heater cord across the engine cowl as shown.

  12. Object Number: 341099  Size: SH
  13. Route and secure the heater cord to the VCM wiring harness.
  14. Fill the reservoir with engine coolant. Refer to Cooling System Draining and Filling .
  15. Inspect the system for leaks.