The pump circulates coolant throughout the system while the engine is running. If the drive belt fails, the water pump will not function. It is one of the reasons it’s so important to always check the status of the belt during maintenance. The water pump uses centrifugal force to send coolant to the outside while it spins, drawing coolant from the center continuously. The pump inlet is located close to the center so that coolant returning from the radiator strikes the pump vanes, which then fling the coolant to the outside of the pump to enter the engine. Coolant leaving the pump first flows through the engine block and cylinder head, then through the radiator and finally back to the pump.