How do you replace the thermostat located on a 1998 Chevy Cavalier?
First you want to reduce the coolant level by taking some coolant out of the system.You do this by removing radiator cap and then you locate the radiator drain plug at the front of the car not on the engine side on the driver side front radiator tank. You drain in to a clean pan. Next below the alternator you will see a housing jutting out from the engine that is the thermostat housing.Remove the hose that connected to this housing then remove the two 8mm bolts and you will see the thermostat with a rubber seal. Replace thermostat with new seal. Reinstall reverse procedure. But you will have to bleed the air from system on the coolant return pipe under the coil pack. You will see a 9/32 brass bolt threaded into this pipe.With engine NOT running loosen and wait until coolant flows from the pipe and no more air bubbles coming out .Now top off your coolant. Your finished.