Cooling Circuits - Subaru LEGACY 2002 Quick Reference Index

2. Cooling Circuits

The cooling system operates in three different phases depending on the temperature of the engine
coolant.
! 1st phase (thermostat closed)
When the engine coolant temperature is below 76°C (169°F), the thermostat remains closed. The
coolant flows through the bypass and heater circuits.
This permits the engine to warm up quickly.
! 2nd phase (thermostat open)
When the engine coolant temperature is above 76 – 80°C (169 – 176°F), the thermostat opens.
The coolant flows through the radiator where it is cooled.
! 3rd phase (thermostat open and radiator fan operating)
When the engine coolant temperature sensor sends a signal indicating a temperature above 95°C
(203°F) to the ECM, it causes the radiator fan (or fans) to operate.
COOLING CIRCUITS
Thermostat
CO-3
Cooling
B2H2915B