Engine Coolant Thermostat Replacement 4.3L

1. Remove the air cleaner and the duct assembly. Refer to Air Cleaner Outlet Resonator Replacement .
2. Partially drain the coolant. Refer to Cooling System Draining and Filling .
3. Remove the coolant recovery reservoir. Refer to Coolant Recovery Reservoir Replacement .
4. 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.

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. Install the thermostat.
2. Install the thermostat housing to the intake manifold.

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. Install the bolts to the housing.

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




4. Connect the radiator hose to the thermostat housing.
5. Install the coolant recovery reservoir. Refer to Coolant Recovery Reservoir Replacement .
6. Install the air cleaner and the duct. Refer to Air Cleaner Outlet Resonator Replacement .
7. Refill the cooling system. Refer to Cooling System Draining and Filling .
8. Bleed the air from the cooling system.
9. Inspect the thermostat housing and the gasket for coolant leaks.

Engine Coolant Thermostat Replacement 5.0L and 5.7L

1. Remove the air cleaner and the duct assembly. Refer to Air Cleaner Assembly Replacement in Engine Controls.
2. Partially drain the coolant. Refer to Cooling System Draining and Filling .
3. Remove the coolant recovery reservoir. Refer to Coolant Recovery Reservoir Replacement .
4. 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.

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. Install the thermostat.
2. Install the thermostat housing to the intake manifold.




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. Install the bolts to the housing.

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




4. Connect the radiator hose to the thermostat housing.
5. Install the coolant recovery reservoir. Refer to Coolant Recovery Reservoir Replacement .
6. Install the air cleaner and the duct. Refer to Air Cleaner Assembly Replacement in Engine Controls.
7. Refill the cooling system. Refer to Cooling System Draining and Filling .
8. Bleed the air from the cooling system.
9. Inspect the thermostat housing and the gasket for coolant leaks.

Engine Coolant Thermostat Replacement 6.5L

1. Remove the air cleaner and the duct assembly. Refer to Air Cleaner Assembly Replacement in Engine Controls.
2. Partially drain the coolant. Refer to Cooling System Draining and Filling .
3. Remove the surge tank. Refer to Radiator Surge Tank Replacement .
4. 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 thermostats.
8. Clean the gasket mating surfaces.

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.

Important: Thermostats must be replaced in pairs.

1. Install the thermostats.
2. Install the thermostat housing to the intake manifold.

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. Install the bolts to the housing.

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




4. Connect the radiator hose to the thermostat housing.
5. Install the surge tank. Refer to Radiator Surge Tank Replacement .
6. Install the air cleaner and the duct. Refer to Air Cleaner Assembly Replacement in Engine Controls.

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

7. Refill the cooling system. Refer to Cooling System Draining and Filling .
8. Bleed the air from the cooling system.
9. Inspect the thermostat housing and the gasket for coolant leaks.

Engine Coolant Thermostat Replacement 8.1L

1. Disconnect the following electrical connectors:

•	Mass airflow (MAF) sensor (1)

•	Intake air temperature (IAT) sensor (2)




2. Loosen the clamp at the air cleaner.
3. Remove the air cleaner bolts.
4. Remove the air cleaner.



5. Loosen the clamp (2) at the throttle body (1).
6. Remove the air cleaner duct (3).



7. Drain the coolant until the level is below the thermostat.
8. Loosen the inlet hose clamp at the thermostat housing.
9. Remove the inlet hose (1) from the housing.



10. Remove the thermostat housing bolts (2).
11. Remove the thermostat housing (1).
12. Remove the thermostat (3).

1. Install the thermostat (3).
2. Install the thermostat housing (1).

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. Install the thermostat housing bolts (2).

Tighten
Tighten the thermostat housing bolts to 30 N·m (22 lb ft).




4. Install the inlet hose (1) to the thermostat housing.
5. Tighten the inlet hose clamp.



6. Install the air cleaner duct (3).
7. Position and tighten the clamp (2) at the throttle body (1).

Tighten
Tighten the air cleaner duct clamp to 4 N·m (35 lb in).




8. Install the air cleaner.
9. Install the air cleaner bolts.

Tighten
Tighten the air cleaner bolts to 10 N·m (89 lb in).

10. Tighten the clamp at the air cleaner.

Tighten
Tighten the air cleaner duct clamp to 4 N·m (35 lb in).




11. Connect the following electrical connectors:

•	MAF sensor (1)

•	IAT sensor (2)

12. Add coolant until the correct level is reached.