How to Set the Thermostat in a 2002 Pontiac Sunfire

The 2002 Pontiac Sunfire came equipped with the 2.2-liter or 2.4-liter engine models. You will find slight differences within the 2.2L model. When replacing the thermostat, look up the eighth digit of your vehicle identification number (VIN) on the left corner of the dashboard, inside the windshield. Use this number or letter to refer to the corresponding section to remove and install the thermostat on your Sunfire.

Things You'll Need

• Ratchet
• Ratchet extension
• Socket set
• Catch pan
• Plastic scraper
• Wire brush
• Torque wrench
• New antifreeze, if necessary
• Distilled water, if necessary
• Lug wrench, for 2.4L model
• Floor jack, for 2.4L model
• 2 jack stands, for 2.4L model
• 2 chocks, for 2.4L model

Instructions

Removing the Thermostat on a 2.2L VIN 4 and F Models

1. Remove the exhaust manifold using a ratchet, ratchet extension and socket, if you have a VIN F model with an automatic transmission.

2. Place a catch pan under the radiator drain plug. Open the radiator drain plug and remove the coolant from the radiator. Then, close the radiator plug.

3. Detach the lower radiator hose from the thermostat housing on the engine side using a ratchet, ratchet extension and socket. On the VIN F model, you do not have to disconnect the radiator hose.

4. Unfasten the thermostat housing bolts using a ratchet, ratchet extension and socket. Then, detach the thermostat housing. This applies to both VIN 4 and F models.

5. Make a note of the exact position of the thermostat on its housing so that you install the new unit in the same position. Then, remove the thermostat and gasket.

6. Clean the thermostat housing using a plastic scraper and wire brush.

Installing the New Thermostat on the 2.2L VIN 4 and F Models

1. Position the new thermostat and gasket in place.

2. Set the thermostat housing in position and start the mounting bolts by hand, using the ratchet extension and socket. Tighten the mounting bolts to 10-foot lbs. (14 Nm) using a torque wrench. On the VIN F models, torque the mounting bolts to 8-foot lbs. (10 Nm).

3. Attach the lower radiator hose to the thermostat housing using the ratchet, ratchet extension and socket (except VIN F models).

4. Install the exhaust manifold using a ratchet, ratchet extension and socket, if you have a VIN F model with an automatic transmission.

5. Refill the cooling system with the coolant you drained before or, if two years old, replace it with a new mixture of 50 percent antifreeze and 50 percent distilled water.

6. Check for leaks.

Removing the Thermostat on a 2.4L VIN T Model

1. Place a catch pan under the radiator drain plug. Open the radiator drain plug and remove the coolant from the radiator. Then, close the radiator plug.

2. Detach the heat shield from the exhaust manifold using a ratchet, ratchet extension and socket.

3. Follow the lower radiator outlet pipe where it connects with the coolant inlet housing at the engine side. Then, unfasten and remove the housing bolts using a ratchet, ratchet extension and socket.

4. Loosen the front, passenger-side wheel/tire lugs using a lug wrench.

5. Lift the front of your Pontiac Sunfire using a floor jack and support it on two jack stands.

6. Chock the rear wheels.

7. Look at the lower radiator outlet pipe where it connects to the inlet housing at the radiator side. Find the stud just underneath the inlet housing at the radiator and remove the stud using a ratchet, ratchet extension and socket.

8. Finish removing the front passenger-side wheel/tire assembly using a lug wrench.

9. Detach the outlet pipe transaxle-to-engine block brace using the ratchet, ratchet extension and socket.

10. Remove the radiator outlet pipe.

11. Look at the mounting position of the thermostat so that you can install the new unit in the same position. Then, remove the thermostat and gasket.

Installing the Thermostat on the 2.4L VIN T Model

1. Clean the thermostat mounting surface using a plastic scraper and brush.

2. Install new thermostat and gasket in place.

3. Attach the outlet pipe transaxle-to-engine block brace using the ratchet, ratchet extension and socket.

4. Install the front, passenger-side wheel/tire assembly using the lug wrench.

5. Install the stud underneath the inlet housing of the outlet pipe at the radiator side using the ratchet, ratchet extension and socket.

6. Lower your Pontiac Sunfire.

7. Install the mounting bolts to the outlet pipe where it connects with the coolant inlet housing on the engine side. Use the ratchet, ratchet extension and socket.

8. Attach the heat shield to the exhaust manifold using the ratchet, ratchet extension and socket.

9. Refill the cooling system with the coolant you drained before or, if two years old, replace it with a new mixture of 50 percent antifreeze and 50 percent distilled water.

10. Check both sides of the radiator outlet pipe for leaks.

Tips & Warnings

• Never drain the cooling system while the engine is hot. Wait at least 30 minutes before opening the radiator cap or coolant reservoir to avoid serious skin burns or other personal injuries.

References

• "General Motors Chevrolet Cavalier & Pontiac Sunfire: 1995 thru 2004 (Haynes Repair Manual)"; John H. Haynes and Mark Ryan; 2005