Engine coolant thermostat with overtemperature protection

摘要

An engine coolant thermostat of the type having a thermally expansible wax power element acting against a diaphragm and piston to move a poppet. The poppet has a retainer attached thereto which has portions sliding in slots on the thermostat housing; and these portions contact the ends of the slots to limit piston travel in the event of exposure to overtemperature and prevent failure of the thermostat.