The cooling system maintains proper engine temperature under all operating conditions. When the engine is cold, coolant in the radiator does not circulate, allowing for faster engine warm-up.

The thermostat remains closed until the engine reaches the proper operating temperature. Once the engine reaches normal operating temperature, the thermostat opens, and the coolant circulates through the crossflow radiator in order to keep the engine from overheating.

The cooling system includes the following components:

In the Northstar cooling system, the coolant pump takes coolant from the radiator and passes the coolant through the thermostat on the inlet side of the coolant pump. The coolant enters the block at the rear of the engine from the water crossover, then the coolant is routed through the cylinder heads back to the water crossover. At this point the coolant has four possible routes: