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 80°C (176°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 80 - 84°C (176 - 183.2°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 91°C (196°F) to the ECM, it causes the radiator fan (or fans) to operate.