Repair 7

How to Change the Thermostat on a 4 3 GMC Sierra

The thermostat in the 4.3-liter GMC Sierra pickup truck regulates operating temperatures within the engine to prevent overheating and premature engine failure. This is a big task for a very small, inexpensive part. When the thermostat stops regulating properly, you will notice the temperature gauge in the dash start to rise. You will smell the sweet odor of overheating coolant and your truck will eventually pour steam out of the engine bay. Changing the thermostat is a fairly easy job that shouldnt take you very long at all.

Instructions

1

Lift the hood and prop it open. Position a drain pan under the drain valve on the bottom of the radiator. Loosen the radiator cap. Open the valve with a pliers. Drain two gallons of coolant into a clean drain pan. Close the drain valve with the pliers.

2

Follow the upper radiator hose to the thermostat housing, behind the alternator.

3

Remove the two bolts that secure the housing to the engine. Hose removal is not necessary to remove the thermostat housing.

4

Lift the housing up and shove it and the hose out of your way.

5

Pull the old thermostat out of the engine and place the new one in. You must place the new one into the engine and orientate it in the same manner as the old one.

6

Lift the old gasket off the engine, wipe down the surface with a clean towel and place the new thermostat gasket into place.

7

Place the thermostat housing back on the engine and bolt it into place.

8

Remove the radiator cap. Pour the two gallons of fluid back into the radiator. Replace and tighten the cap. Close the hood.