1995-1997 Mazda B2300 2.3L. 1995-1997 Ford Ranger 2.3L. 1995-1997 Ford Ranger 3.0L. 1995-1997 Ford Ranger 4.0L. It is part of the engine's cooling system, which also includes a liquid coolant, hoses to circulate the coolant, a fan, and a thermostat that monitors the coolant temperature.
