GM 91171047 Thermostat, Engine Coolant 92Deg

Check three basic things before thinking the thermostat needs replacing: coolant level, belt tension, and temperature gauge functioning. When your engine takes too long to heat up both inside the car with the heater and despite normal temperature indicator readings, your thermostat may be blocked open inside and needs replacing. To see if a stuck thermostat is making the engine hot, check the upper radiator hose with your hand; if the hose isn't warm but the engine is, the thermostat needs to be replaced because it's not letting fresh coolant go into the radiator. Caution: Driving without a thermostat can make your car's computer stay in an inefficient mode, which hurts both how much gas you use and how much pollution you make. When the top radiator hose feels hot, that means the engine's cooling liquid is traveling and the thermostat valve is open. Unplug the negative battery cable. Completely remove and save any good coolant from inside the car. Pull out the air filter, see where the upper radiator hose leads you to find the thermostat housing. First take off the hose clamp with your hands, and remove the hose. If it won't budge, use pliers to get it unstuck. Damage to the outside of the housing cover means the entire cover needs to be replaced. First, unbolt everything and take off the housing cover and bracket, knowing coolant might leak onto the ground. Take note of where the thermostat goes in before you remove it. After that, clean all touchpoints on the thermostat. Put the thermostat into the housing, having the air bleed pointing right and the spring part facing the engine. Place a new gasket on top of the thermostat, and put the cover back with its bolts. Tighten all bolts to the required force. Close the hose connector by putting the hose back to the fitting, then screw the hose clasp tight. Recover all coolant, start the engine, let it run for a while, then check for leaks and see that the thermostat works correctly as intended.