Thermostat Housing: Description and Operation

The plastic thermostat housing is installed between the two cylinder banks immediately above the coolant pump. Controlling the coolant flow through the radiator, the thermostat starts to open at 80°-84° C (176°-183° F) and is fully-open at 96° C (205° F).

A duct in the cylinder block connects the thermostat housing outlet to the pump inlet and a stub pipe connects the duct-to-air conditioning heater return pipe. The joint between the thermostat housing and the cylinder block is via an in-groove gasket seal.

In addition to containing the thermostat; the plastic housing incorporates connections for the bleed, bypass and radiator bottom hoses. The bleed outlet vents any air in the system into the vehicle's coolant reservoir. A removable filler cap allows air out of the system when filling from empty.