GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 38185 Hose Clamp Pliers

Removal Procedure

  1. Drain the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.

  2. Object Number: 663610  Size: SH
  3. UseJ 38185 in order to position aside the heater hose inlet and outlet clamp from the heater core.
  4. Disconnect the inlet and outlet heater hose from the heater core.
  5. Important: Cap off the pipes in order to prevent coolant spillage inside the vehicle.

  6. Cap off the heater core pipes.
  7. Remove the IP trim pad. Refer to Instrument Panel Trim Pad Replacement in Instrument Panel, Gages and Console.

  8. Object Number: 508311  Size: SH

    Important: Position the heater core cover downward and rearward in order to disconnect the cover from the rear area floor duct assembly.

  9. Remove the screws from the heater core outlet cover.
  10. Remove the heater core outlet cover.

  11. Object Number: 295349  Size: SH
  12. Remove the screws from the heater core cover.
  13. Remove the heater core cover.

  14. Object Number: 143978  Size: SH
  15. Remove and discard the seals (1,2,3) from the heater core cover.

  16. Object Number: 296242  Size: SH
  17. Remove and discard the heater core outer seal (5) from the heater core.

  18. Object Number: 295351  Size: SH
  19. Remove the heater core clamp screw (1).
  20. Remove the heater core retaining clamp.
  21. Remove the pipe retainer clamp screw (2) from the heater core.

  22. Object Number: 295353  Size: SH
  23. Remove the heater core from the lower case of the HVAC module assembly.

  24. Object Number: 143987  Size: SH
  25. Remove and discard the lower seal (4) from the HVAC module assembly case.

  26. Object Number: 143992  Size: SH
  27. Remove and discard the center seal (3) from the HVAC module assembly case.

  28. Object Number: 143985  Size: SH
  29. Remove and discard the upper seal (2) from the HVAC module assembly lower case.

  30. Object Number: 143990  Size: SH
  31. Remove and discard the side seals (1) from the HVAC module assembly lower case.

Installation Procedure


    Object Number: 143990  Size: SH
  1. Install the side seals (1) to the HVAC module assembly lower case.

  2. Object Number: 143985  Size: SH
  3. Install the upper seal (2) to the HVAC module assembly lower case.

  4. Object Number: 143992  Size: SH
  5. Install the center seal (3) to the HVAC module assembly case.

  6. Object Number: 143987  Size: SH
  7. Install the lower seal (4) to the HVAC module assembly case.

  8. Object Number: 295353  Size: SH
  9. Install the heater core to the lower case of the HVAC module assembly.

  10. Object Number: 295351  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.

  11. Install the screw (2) to the heater core line clamp.
  12. Tighten
    Tighten the screw to 1.5 N·m (13 lb in).

  13. Install the screw (1) which secures the heater core mounting clip.
  14. Tighten
    Tighten the screw to 1.5 N·m (13 lb in).


    Object Number: 296242  Size: SH
  15. Install heater core outer seal (5) to the heater core.

  16. Object Number: 143978  Size: SH
  17. Install new seals (1,2,3) to the heater core cover.

  18. Object Number: 295349  Size: SH
  19. Install the heater core cover.
  20. Install the screws which secure the heater core cover.
  21. Tighten
    Tighten the screws to 1.5 N·m (13 lb in).


    Object Number: 508311  Size: SH
  22. Install the heater core outlet cover.
  23. Install the screws which secure the heater core outlet cover.
  24. Tighten
    Tighten the screws to 1.5 N·m (13 lb in).

  25. Install the IP trim pad. Refer to Instrument Panel Trim Pad Replacement in Instrument Panel, Gages and Console.

  26. Object Number: 663610  Size: SH
  27. Connect the inlet and outlet heater hose to the heater core .
  28. Important: Position the heater hose clamps in the indicated location

  29. UseJ 38185 in order to reposition the heater hose inlet and outlet clamp to the heatrer core.
  30. Filll the coolant. Refer to Cooling System Draining and Filling in Engine Cooling.