1
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Coolant bypass tube connection
3
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Engine degas hose connection
4
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Engine coolant temperature (ETC) sensor
5
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Radiator upper coolant hose connection
7
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Thermostat housing engine coolant intake chamber
The thermostat is built into the thermostat housing and cannot be serviced as a separate component.
The thermostat housing also acts as the engine coolant outlet connector and houses the ECT sensor. The ECT sensor is a push fit and is held in place by a retaining clip.
When the engine coolant is below 88°C, the thermostat is in the closed position. This restricts the flow of coolant through the radiator upper coolant hose and allows the coolant from the engine to be circulated through the coolant bypass tube and the coolant pump back to the engine cylinder block, speeding up the warm up process.
When the engine coolant reaches 88°C, the thermostat begins to open, allowing coolant to flow through the upper radiator coolant hose to the radiator. At the same time, the opposite end of the thermostat closes off the coolant bypass tube coolant flow. This forces the coolant pump to pull coolant from the radiator through the lower radiator coolant hose.
At all times the heater core receives heated coolant from the engine cylinder block through the thermostat housing. The coolant is cooled by the heater core and its connecting coolant hoses and then returned to the coolant pump through the coolant bypass tube.
