GM Service Manual Online
For 1990-2009 cars only
Makes 🢒 Chevrolet 🢒 1996 🢒 Chevy G Van 🢒 Engine 🢒 Engine Cooling 🢒 Engine Coolant Thermostat Replacement

Removal Procedure

    Notice: When adding coolant, use DEX-COOL® coolant. If silicated coolant is added to the system, premature engine, heater core or radiator corrosion may result. In addition, the engine coolant will require change sooner-at 50 000 km (30,000 mi) or 24 months.

  1. Remove the air cleaner and duct assembly. Refer to Engine Controls.
  2. Remove the coolant recovery reservoir or the surge tank (Diesel).
    3. • For the recovery reservoir, refer to Coolant Recovery Reservoir Replacement .
    • For the surge tank, refer to Surge Tank (Diesel) .
  3. Partially drain the coolant. Refer to Cooling System Draining and Filling .

    4. Object Number: 48323 Size: SH
  4. For the 4.3L, disconnect the radiator hose from the thermostat housing.
  5. Remove the bolts attaching the thermostat housing to the thermostat.
  6. Remove the thermostat housing.
  7. Remove the thermostat.
  8. Clean the gasket mating surfaces.

    9. Object Number: 72725 Size: SH
  9. For the 5.0L and the 5.7L, disconnect the radiator hose from the thermostat housing.
  10. Remove the bolts attaching the thermostat housing to the thermostat.
  11. Remove the thermostat housing.
  12. Remove the thermostat.
  13. Clean the gasket mating surfaces.

    14. Object Number: 72728 Size: SH
  14. For the 7.4L, disconnect the radiator hose from the thermostat housing.
  15. Remove the bolts attaching the thermostat housing to the thermostat.
  16. Remove the thermostat housing.
  17. Remove the thermostat.
  18. Clean the gasket mating surfaces.

    19. Object Number: 82158 Size: SH
  19. For the 6.5L diesel engine, disconnect the radiator hose from the thermostat housing.
  20. Remove the bolts attaching the thermostat housing to the thermostat.
  21. Remove the thermostat housing.
  22. Remove the thermostat.
  23. Clean the gasket mating surfaces.

Installation Procedure

    Object Number: 48323 Size: SH
  1. For the 4.3L, install the thermostat.
  2. Install the thermostat housing to the intake manifold.
  3. Install the bolts to the housing.

    4. Tighten
    Tighten the bolts to 25 N·m (18 lb ft).

    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: 72725 Size: SH
  4. For the 5.0L and 5.7L, install the thermostat.
  5. Install the thermostat housing to the intake manifold.
  6. Install the bolts to the housing.

    7. Tighten
    Tighten the bolts to 25 N·m (18 lb ft).


    Object Number: 72728 Size: SH
  7. For the 7.4L, install the thermostat.
  8. Install the thermostat housing to the intake manifold.
  9. Install the bolts to the housing.

    10. Tighten
    Tighten the bolts to 40 N·m (30 lb ft).


    Object Number: 82158 Size: SH
  10. For the diesel engines, install the thermostat.
  11. Install the thermostat housing to the intake manifold.
  12. Install the bolts to the housing.

    13. Tighten
    Tighten the bolts to 42 N·m (31 lb ft).

  13. Connect the radiator hose to the thermostat housing.
  14. Install the coolant recovery reservoir or surge tank.
    15. • For the recovery reservoir, refer to Coolant Recovery Reservoir Replacement .
    • For the surge tank, refer to Surge Tank (Diesel) .
  15. Install the air cleaner and the duct. Refer to Engine Controls.

    16. Important: In order to properly fill a system that has been completely drained, use the air bleed vents, located on the thermostat housing.

  16. Refill the coolant. Refer to Cooling System Draining and Filling .
  17. Inspect the thermostat housing and the gasket for coolant leaks.