Cooling System Circulation

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:
- The radiator
- The heater core
- The throttle body heater circuit
- The generator cooling circuit