Engine Coolant Thermostat Replacement LA3, LY9

1. Remove the thermostat housing. Refer to Engine Coolant Thermostat Housing Replacement .



2. Complete the following in order to remove the thermostat from the thermostat housing:

2.1.	Depress the ears on both sides of the thermostat.

2.2.	Rotate the thermostat until it clears the retaining feature of the housing.

2.3.	Release the pressure from the thermostat.

2.4.	Pull the thermostat from the thermostat housing.

1. Complete the following in order to Install the thermostat into the thermostat housing:

1.1.	Align the thermostat pin to the thermostat housing orifice.

1.2.	Depress the ears on both sides of the thermostat.

1.3.	Rotate the thermostat until it aligns with the retaining feature of the housing.

1.4.	Release the pressure from the thermostat.

2. Install the thermostat housing. Refer to Engine Coolant Thermostat Housing Replacement .

Engine Coolant Thermostat Replacement LY7

1. Partially drain the cooling system. Refer to Cooling System Draining and Filling.

Important: Do NOT separate the upper and lower intake manifolds.

2. Remove the upper intake manifold with the lower intake manifold. Refer to Lower Intake Manifold Replacement.
3. Disconnect the surge tank hose from the thermostat.



4. Remove the coolant pipe/thermostat housing bolt (2).
5. Remove the coolant pipe upper bolt (7).
6. Remove the coolant inlet pipe (4) from the thermostat.



7. Remove the thermostat bolts.
8. Remove the thermostat and discard the thermostat seal.

1. Install the thermostat with a NEW thermostat seal.

Notice: Refer to Fastener Notice in the Preface section.

2. Install the thermostat bolts.

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




3. Install the coolant pipe (4), NEW seal, and fasteners (2 and 7). Refer to Engine Coolant Inlet Pipe Replacement.
4. Install the surge tank hose to the thermostat.
5. Install the upper intake manifold with the lower intake manifold. Refer to Lower Intake Manifold Replacement.
6. Fill the cooling system. Refer to Cooling System Draining and Filling.

Engine Coolant Thermostat Replacement LS6

Important: The water pump inlet (thermostat housing) and thermostat MUST be replaced as an assembly. The thermostat is not serviceable separately.

1. Drain the cooling system. Refer to Cooling System Draining and Filling .
2. Remove the cooling fan assembly. Refer to Engine Cooling Fan Replacement .
3. Reposition the outlet hose clamp at the water pump inlet.
4. Remove the outlet hose from the water pump inlet.
5. Remove the thermostat housing bolts.
6. Remove the thermostat housing.



7. The thermostat and O-ring seal are integral to the thermostat housing.

1. Install a new thermostat housing.
2. Ensure that the new thermostat housing has an O-ring seal and is in the groove correctly.



3. Install the thermostat housing (with thermostat).

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.

4. Install the thermostat housing bolts.

Tighten
Tighten the thermostat housing bolts to 15 N·m (11 lb ft).

5. Install the outlet hose to the thermostat housing.
6. Position the outlet hose clamp at the thermostat housing.
7. Install the cooling fan assembly. Refer to Engine Cooling Fan Replacement .
8. Fill the cooling system. Refer to Cooling System Draining and Filling .