For 1990-2009 cars

## Engine Coolant Thermostat Replacement 2.4 L

### Removal Procedure

Notice: When adding coolant, it is important that you use GM Goodwrench DEX-COOL™ coolant. If coolant other than DEX-COOL™ is added to the system, the engine coolant will require change sooner: at 50 000 km (30,000 miles) or 24 months.

Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

1. Disconnect the negative battery cable.
2. Drain and recover the coolant.

Refer to Cooling System Draining and Filling .

3. Remove the exhaust manifold heat shield.
4. Remove the coolant inlet housing bolt through the exhaust manifold.
5. Raise and suitably support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
6. Remove the coolant inlet housing stud from the oil pan.
7. Remove the second coolant inlet housing bolt.
8. Remove the coolant inlet housing.
9. Remove the thermostat.
10. Clean the mating surfaces.

### Installation Procedure

1. Install the thermostat.
2. Install the inlet housing.
3. Install the gasket.

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 coolant inlet housing bolt.

Tighten
Tighten the bolt to 14 N·m (124 lb in).

5. Install the coolant inlet housing stud to oil pan.

Tighten
Tighten the bolt to 26 N·m (19 lb ft).

6. Lower the vehicle.
7. Install the coolant inlet housing bolt through the exhaust manifold.

Tighten
Tighten the bolt to 14 N·m (123 lb in).

8. Install the exhaust manifold heat shield.
9. Fill the cooling system.

Refer to Cooling System Draining and Filling .

10. Connect the negative battery cable.

Tighten
Tighten the bolt to 16 N·m (12 lb ft).

11. Inspect the system for leaks.

## Engine Coolant Thermostat Replacement 3.1 L

### Removal Procedure

Caution: Unless directed otherwise, the ignition and start switch must be in the OFF or LOCK position, and all electrical loads must be OFF before servicing any electrical component. Disconnect the negative battery cable to prevent an electrical spark should a tool or equipment come in contact with an exposed electrical terminal. Failure to follow these precautions may result in personal injury and/or damage to the vehicle or its components.

1. Disconnect the negative battery cable.
2. Drain and recover the coolant.

Refer to Cooling System Draining and Filling .

3. Remove the air cleaner assembly.
4. Remove the surge tank line from the coolant outlet.
5. Remove the coolant outlet to the inlet manifold attaching bolts.
6. Remove the coolant outlet.
7. Remove the thermostat.
8. Clean the inlet manifold mating surfaces.
9. Clean the coolant outlet mating surfaces.

### Installation Procedure

1. Install the thermostat in the inlet manifold.
2. Install the coolant outlet to the inlet 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 attaching bolts.

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

4. Install the air cleaner assembly.
5. Install the surge tank line to the coolant outlet.
6. Fill the engine coolant.

Refer to Cooling System Draining and Filling .

7. Connect the negative battery cable.

Tighten
Tighten the bolt to 16 N·m (12 lb ft).

8. Inspect the system for leaks.