The motor mount in a Pontiac Sunfire is designed to dampen engine vibrations. This mount also allows the motor to shift under load when the car is accelerating. As time passes, the motor mount loses its ability to dampen engine vibrations. This can result in increased vibration inside the car and engine stalling. Replacement motor mounts are available from automotive salvage yards, auto parts stores and licensed General Motors dealerships.
Shift the Sunfire's transmission into park (automatic transmission) or first gear (manual transmission). Turn off the engine and set the parking brake.
Open the hood and disconnect the negative battery lead using an 8-mm box-end wrench. Place wheel chocks behind the rear wheels.
Place an automotive jack underneath the engine and raise it until it's touching the bottom of the oil pan. This will support the engine while the motor mount is being replaced.
Remove the two 15-mm bolts holding the motor mount to the engine using a 3/8-inch ratchet and 15-mm socket. Remove the three 13-mm nuts holding the motor mount to the body of the car using a 3/8-inch ratchet and 13-mm socket. Remove the motor mount from the vehicle.
Position the new motor mount inside the engine bay, and reinstall the three 13-mm nuts to secure the motor mount to the body. Raise the automotive jack until the engine lines up with the mounting holes on the other side of the motor mount. Reinstall the two 15-mm bolts to secure the motor mount to the engine.
Reconnect the negative battery lead and remove the jack from underneath the engine. Start the engine.
