GM 12559338 Thermostat,Engine Coolant

You can Select Your Vehicle to check if 12559338 fits your vehicle.

Don't drive without a thermostat; it impacts emissions and fuel economy. Before replacing the thermostat, inspect coolant level, drivebelt tension, and gauge operation. A slow-warming engine indicates an open thermostat, while an overly hot engine with a cool upper radiator hose suggests a closed one. Overheating can cause damage like leaking head gaskets and warped cylinder heads. To replace the thermostat, drain some coolant from the radiator until below the thermostat housing. Disconnect the upper radiator hose, remove the housing cover, and note the thermostat's position. Clean off old gasket remnants, then clean the surfaces with acetone. Apply ATV sealant, position the new thermostat, and attach a new gasket. Secure the cover, reattach the hose, and refill the coolant system. After running the engine, check for leaks.

Begin by draining about three quarts of coolant from the radiator until the level is below the thermostat housing.