Legacy F4-2.5L DOHC Turbo (2005)
Radiator Cooling Fan Motor Relay: Description and Operation
Cooling Circuits
The cooling system operates in three different phases depending on the temperature of the engine coolant.
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1st phase (thermostat closed)
When the engine coolant temperature is below the preset temperature, the thermostat remains closed. The coolant flows through the heater circuit.
This permits the engine to warm up quickly.
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2nd phase (thermostat open)
When the engine coolant temperature becomes higher than the preset temperature, the thermostat opens. The coolant flows through the radiator
where it is cooled.
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3rd phase (thermostat open and radiator fan operating)
When the engine coolant temperature sensor becomes hotter than the preset value, the ECM receives signals from the engine coolant temperature
sensor and causes the radiator fan(s) to operate. When the engine is stopped after high-speed operation, vapor produced in the turbocharger
cooling section flows from the coolant filler tank to the reservoir tank where it condenses back into water. Water is then absorbed by the coolant
filler tank as the engine cools down.