For 1990-2009 cars

A wax pellet-type thermostat (1) is used to control the flow of coolant through the cooling system. The thermostat is mounted in the thermostat housing in the front of the intake manifold. The thermostat stops the flow of coolant from the engine to the radiator in order to provide faster warm-ups and to regulate the coolant temperature.

The wax pellet is hermetically sealed in a metal case. The wax element expands when heated and contracts when cooled. As the vehicle is driven and the engine warms up, the coolant temperature increases. When the coolant reaches a specified temperature, the wax pellet element expands and exerts pressure against a metal case, forcing the valve open. This allows coolant to flow through the system and cool the engine. As the pellet cools, the contraction allows a spring to close the valve.

The thermostat used in this vehicle is calibrated to begin opening at 82°C (179°F) and be fully open (more than 8 mm [0.31 in] valve lift) at 95°C (203°F).

An air bleed valve (2) is provided in the top portion of the thermostat to vent gas or air which may have penetrated the cooling system.