How to Change the Thermostat in a 1999 Chevy Cavalier 2.2 Liter Engine

A cold engine requires more fuel to run properly, resulting in an increased level of emissions. The thermostat in your 1999 Cavalier helps the engine warm up to operating temperature faster, for improved performance and fuel mileage. The thermostat also controls the flow of coolant through the engine to prevent overheating while maintaining a stable operating temperature. Overheating the engine will damage the heat-activated spring that controls the opening temperature of the thermostat. Located in the lower radiator hose neck, the thermostat should be replaced if the engine starts to overheat.

Instructions

1

Block the Cavalier's rear wheels with wheel chocks. Lift the front driver-side of the vehicle, using a floor jack positioned under the reinforced lifting point, which is located a few inches behind the front wheel opening, on the lower rocker panel pinch weld. Slide a jack stand under the pinch weld, next to the jack, for safety.

2

Remove the splash shield screws that attach the splash shield to the front bumper below the radiator, using an 8-mm socket and ratchet. Remove the splash shield. Position a drain pan under the driver-side radiator tank. Open the petcock valve on the bottom of the driver-side radiator tank and allow the coolant to drain into the drain pan.

3

Remove the lower hose from the coolant neck, which is located to the left of the exhaust manifold, just below the alternator mounting bracket. Use hose clamp pliers to open the hose clamp, then twist the hose while pulling it off the coolant neck.

4

Remove the coolant neck bolts, using a 10-mm socket and ratchet. Pull the coolant neck off the coolant pipe to expose the thermostat. Clean the gasket surfaces on the coolant neck, as well as the coolant pipe, using a wire brush.

5

Install the new thermostat in the reverse order of removal, using a new O-ring seal around the thermostat, with the spring side of the thermostat pointing towards the engine. Torque the coolant neck bolts to 19 foot-pounds, using a torque wrench. Reinstall the lower radiator hose. Close the petcock valve on the radiator. Slide the drain pan from under the Cavalier and reinstall the splash shield.

6

Remove the jack stand and lower the car to the ground. Unscrew the pressure cap from the coolant reservoir and remove the bleeder screw, located on the upper coolant neck -- where the upper radiator hose attaches -- using an 8-mm socket and ratchet.

7

Add the correct mixture of coolant -- according to the season and climate you live in (this information is found in your owners manual) -- to the coolant reservoir until it reaches the "Max" line on the side of the reservoir. Continue to add coolant to the reservoir as the level drops and the coolant flows into the engine.

8

Reinstall the bleeder screw when coolant comes out of the bleeder, and top off the level of coolant in the reservoir. Reinstall the pressure cap and start the engine. Test drive the car to verify that the engine doesn't overheat.