GM Service Manual Online
For 1990-2009 cars only

Heater Core Replacement W/O DO7

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. Remove the fuel injector sight shield. Refer to Fuel Injector Sight Shield Replacement in Engine Mechanical.

  3. Object Number: 422254  Size: SH
  4. Position the J 38185 in order to remove the heater hose clamps.
  5. Remove the heater hoses from the heater core.
  6. Remove the left side sound insulator. Refer to Instrument Panel Insulator Panel Replacement - Left Side in Instrument Panel, Gages and Console.
  7. Remove the right side sound insulator. Refer to Instrument Panel Insulator Panel Replacement - Right Side in Instrument Panel, Gages and Console.

  8. Object Number: 419243  Size: SH

    Important: Due to the difficulty in the removal of the right side screw (2), it will not be necessary to install upon reassembly.

  9. Remove the air distributor duct screws (1,2).
  10. Remove the air distributor duct.

  11. Object Number: 292121  Size: SH
  12. Remove the heater core heat shield screws.
  13. Remove the heater core heat shield.
  14. Remove the heater core cover screws (1).
  15. Remove the heater core cover.
  16. Remove the retaining screw and strap from the heater core.
  17. Remove the heater core.

Installation Procedure

  1. Install the heater core into the HVAC module.
  2. 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.

  3. Secure the heater core into the HVAC module using the attaching straps and screws.
  4. Tighten
    Tighten the screws to 1.4 N·m (12 lb in).

  5. Install the heater core cover.
  6. Ensuring the seals at the front of dash are in the proper positions, install the heater core cover screws.
  7. Tighten
    Tighten the screws to 1.4 N·m (12 lb in).

  8. Install the heater core heat shield.

  9. Object Number: 292121  Size: SH
  10. Install the heater core heat shield screws (1).
  11. Tighten
    Tighten the screws to 1.4 N·m (12 lb in).

  12. Install the air distributor duct.

  13. Object Number: 419243  Size: SH
  14. Install the air distributor duct left side screw (1). Ensure the right tab is seated properly.
  15. Tighten
    Tighten the screw to 1.4 N·m (12 lb in).

  16. Install the left side sound insulator. Refer to Instrument Panel Insulator Panel Replacement - Left Side in Instrument Panel, Gages and Console.
  17. Install the right side sound insulator. Refer to Instrument Panel Insulator Panel Replacement - Right Side in Instrument Panel, Gages and Console.

  18. Object Number: 422254  Size: SH
  19. Install the heater hoses and clamps using the J 38185 .
  20. Install the fuel injector sight shield. Refer to Fuel Injector Sight Shield Replacement in Engine Mechanical.
  21. Fill the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.

Heater Core Replacement W/DO7

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. Remove the fuel injector sight shield. Refer to Fuel Injector Sight Shield Replacement in Engine Mechanical.

  3. Object Number: 422254  Size: SH
  4. Position the J 38185 in order to remove the heater hose clamps.
  5. Remove the heater hoses from the heater core.
  6. Remove the left side sound insulator. Refer to Instrument Panel Insulator Panel Replacement - Left Side in Instrument Panel, Gages and Console.
  7. Remove the right side sound insulator. Refer to Instrument Panel Insulator Panel Replacement - Right Side in Instrument Panel, Gages and Console.

  8. Object Number: 422263  Size: SH
  9. Remove the auxiliary air distribution duct adapter.

  10. Object Number: 419235  Size: SH

    Important: Due to the difficulty in the removal of the right side screw (2), it will not be necessary to install upon reassembly.

  11. Remove the air distributor duct screws (1,2).
  12. Remove the air distributor duct.

  13. Object Number: 292121  Size: SH
  14. Remove the heater core heat shield screws.
  15. Remove the heater core heat shield.
  16. Remove the heater core cover screws (1).
  17. Remove the heater core cover.
  18. Remove the retaining screw and strap from the heater core.
  19. Remove the heater core.

Installation Procedure

  1. Install the heater core into the HVAC module.
  2. 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.

  3. Secure the heater core into the HVAC module using the attaching straps and screws.
  4. Tighten
    Tighten the screw to 1.4 N·m (12 lb in).

  5. Install the heater core cover.
  6. Ensuring the seals at the front of dash are in the proper positions, install the heater core cover screws.
  7. Tighten
    Tighten the screws to 1.4 N·m (12 lb in).


    Object Number: 292121  Size: SH
  8. Install the heater core heat shield and screws (1).
  9. Tighten
    Tighten the screws to 1.4 N·m (12 lb in).

  10. Install the air distributor duct.

  11. Object Number: 419235  Size: SH
  12. Install the air distributor duct left side screw (1). Ensure the right side tab is seated properly.
  13. Tighten
    Tighten the screw to 1.4 N·m (12 lb in).


    Object Number: 422263  Size: SH
  14. Install the auxiliary air distribution duct adapter.
  15. Install the left side sound insulator. Refer to Instrument Panel Insulator Panel Replacement - Left Side in Instrument Panel, Gages and Console.
  16. Install the right side sound insulator. Refer to Instrument Panel Insulator Panel Replacement - Right Side in Instrument Panel, Gages and Console.

  17. Object Number: 422254  Size: SH
  18. Install the heater hoses and clamps using the J 38185 .
  19. Install the fuel injector sight shield. Refer to Fuel Injector Sight Shield Replacement in Engine Mechanical.
  20. Fill the cooling system. Refer to Cooling System Draining and Filling in Engine Cooling.