GM Service Manual Online
For 1990-2009 cars only

Tools Required

J 38185 Hose Clamp Pliers

Removal Procedure

  1. Drain the engine coolant. Refer to Cooling System Draining and Filling .
  2. Remove the right wheel house panel. Refer to Wheelhouse Panel Replacement .
  3. Remove the air cleaner. Refer to the appropriate procedure:
  4. •  Air Cleaner Replacement for the 6.6L (LBZ and LLY) engine
    •  Air Cleaner Replacement for the 8.1L engine
    •  Air Cleaner Replacement for the 7.8L engine
    •  Air Cleaner Replacement for the 7.2L (Caterpillar) engine
  5. Remove the hose clamps using the J 38185 .
  6. Remove the inlet and outlet heater hoses from the heater core.

  7. Object Number: 301592  Size: SH
  8. Remove the screws from the heater assembly.
  9. CAREFULLY open the heater core access door in order to cut the heater core access door.
  10. Cut the marked section of the heater core access door.

  11. Object Number: 301590  Size: SH
  12. Remove the retainers from the heater core.
  13. Remove the heater core.

Installation Procedure


    Object Number: 301590  Size: SH
  1. Install the heater core.
  2. Notice: Refer to Fastener Notice in the Preface section.

  3. Install the heater core retainers.
  4. Tighten
    Tighten the screws to 1.9 N·m (17 lb in).


    Object Number: 301592  Size: SH
  5. Install the heater core access door.
  6. Install the heater core access door retaining screws.
  7. Tighten
    Tighten the screws to 1.9 N·m (17 lb in).

  8. Install the inlet and outlet heater hoses to the heater core.
  9. Install the heater hose clamps using the J 38185 .
  10. Install the right wheelhouse panel. Refer to Wheelhouse Panel Replacement .
  11. Install the air cleaner. Refer to the appropriate procedure:
  12. •  Air Cleaner Replacement for the 6.6L (LBZ and LLY) engine
    •  Air Cleaner Replacement for the 8.1L engine
    •  Air Cleaner Replacement for the 7.8L engine
    •  Air Cleaner Replacement for the 7.2L (Caterpillar) engine
  13. Fill the engine coolant. Refer to Cooling System Draining and Filling .