The thermostat controls the engine's temperature. If working correctly, the temperature gauge should quickly reach the normal temperature. To replace, begin by lifting the vehicle's front, draining the cooling system, and placing a drain pan under the thermostat housing. Remove the housing cover. Note the thermostat's position then remove it. Clean the thermostat housing and cover and install a new seal. Place the thermostat correctly then position the housing cover correctly and screw the bolts. Reattach the radiator hose and fill the radiator up with coolant, then start the engine. Check for leaks.