GM Service Manual Online
For 1990-2009 cars only

Removal Procedure

Tools Required

J 38185 Hose Clamp Pliers

  1. Remove the air cleaner cover and duct assembly. Refer to Air Cleaner Element Replacement in Engine Controls.
  2. Drain the cooling system. Refer to Cooling System Draining and Filling Engine Cooling.
  3. Disconnect the wiper linkage. Refer to Wiper Motor Crank Arm Replacement in Wiper Washer System.

  4. Object Number: 392563  Size: SH
  5. Disconnect both of the heater hoses from the heater core using the J 38185 .
  6. Remove the heater core outlet cover. Refer to Heater Core Cover Replacement .

  7. Object Number: 295349  Size: SH
  8. Remove the screws retaining the heater core cover.
  9. Remove the heater core cover.

  10. Object Number: 143978  Size: SH
  11. Remove and discard the cavity (1), whistle (2), and permagum (3) seals from the heater core cover.

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

  14. Object Number: 295351  Size: SH
  15. Remove the heater core retaining clamp screw (1).
  16. Remove the heater core retaining clamp.
  17. Remove the heater core pipe retainer clamp screw (2).

  18. Object Number: 295353  Size: SH
  19. Remove the heater core from the HVAC module.

  20. Object Number: 143987  Size: SH
  21. Remove and discard the heater core lower seal (4) from the HVAC module case.

  22. Object Number: 143992  Size: SH
  23. Remove and discard the heater core center seal (3) from the HVAC module case.

  24. Object Number: 143985  Size: SH
  25. Remove and discard the heater core upper seal (2) from the HVAC module case.

  26. Object Number: 295355  Size: SH
  27. Remove the heater core pipe retainer clamp from the heater core pipes.
  28. Using a flat bladed tool, release the retaining tab and open the clamp.

Installation Procedure

Tools Required

J 38185 Hose Clamp Pliers


    Object Number: 295355  Size: SH
  1. Install the heater core pipe retainer clamp to the heater core pipes.
  2. Align the depression in the clamp to the ridge on one of the heater core pipes, then close the clamp to secure.


    Object Number: 143990  Size: SH
  3. Install new heater cores side seals (1) to the HVAC module case.

  4. Object Number: 143985  Size: SH
  5. Install a new heater core upper seal (2) to the HVAC module case.

  6. Object Number: 143992  Size: SH
  7. Install a new heater core center seal (3) to the HVAC module case.

  8. Object Number: 143987  Size: SH
  9. Install a new heater core lower seal (4) to the HVAC module case.

  10. Object Number: 295353  Size: SH
  11. Install the heater core to the HVAC module case.
  12. 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.


    Object Number: 295351  Size: SH
  13. Install the heater core pipe retaining clamp screw (2).
  14. Tighten
    Tighten the screw to 1.6 N·m (14 lb in).

  15. Install the heater core retaining clamp.
  16. Install the heater core retaining clamp screw (1).
  17. Tighten
    Tighten the screw to 1.6 N·m (14 lb in).


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

  19. Object Number: 143978  Size: SH
  20. Install a new cavity (1), whistle (2), and permagum (3) seals to the heater core cover.

  21. Object Number: 295349  Size: SH
  22. Install the heater core cover.
  23. Install the heater core cover retaining the screws.
  24. Tighten
    Tighten the screws to 1.6 N·m (14 lb in).

  25. Install the heater core outlet cover. Refer to Heater Core Cover Replacement .

  26. Object Number: 392563  Size: SH
  27. Connect both of the heater hoses and the clamps to the heater core using the J 38185 positioning the clamps as indicated.
  28. Install the wiper linkage. Refer to Wiper Motor Crank Arm Replacement in Wiper Washer System.
  29. Refill the coolant. Refer to Cooling System Draining and Filling in Engine Cooling.
  30. Install the air cleaner cover and duct assembly. Refer to Air Cleaner Element Replacement in Engine Controls.