GM Service Manual Online
For 1990-2009 cars only

Removal Procedure


    Object Number: 1680725  Size: SH
  1. Drain the engine coolant. Refer to Cooling System Draining and Filling .
  2. Disconnect the coolant heater cord (1) from the heater.

  3. Object Number: 1644185  Size: SH

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

  4. Remove the coolant heater.

Installation Procedure


    Object Number: 1644185  Size: SH
  1. Remove any burrs, sealer, paint or other foreign material from the threads/sealing surface of the engine block and from the old coolant heater if the heater is to be reused.
  2. If reusing the old coolant heater, apply thread sealant GM P/N 12346004 (Canadian P/N 10953480), or equivalent to the threads.
  3. Notice: Refer to Component Fastener Tightening Notice in the Preface section.

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


    Object Number: 1680725  Size: SH
  6. Connect the coolant heater cord (1) to the heater.
  7. Fill the cooling system. Refer to Cooling System Draining and Filling .