Phase 1

During an initial engine start-up with an ambient temperature is 60-75°F (16-24°C) or warmer (calibratable) the coolant shutoff solenoid valve closes and the coolant bypass solenoid valve remains closed. With both valves closed the coolant is stagnant and does not circulate in the engine (cylinder block and cylinder head) or through any other cooling system component to significantly decrease the engine warm up time. This reduces emissions and fuel consumption during warm-up.