The water pump operates on centrifugal force. In the center hollow of the pump is the axle on the inside of the pump, connected to a series of vanes, which turn along with the axle. This turning motion creates suction, pulling water from the radiator. The water reaches the pump and is thrown against the exterior walls of the pump by the power of the vanes which are generating the centrifugal force. As the water circles against the outer wall, it presses down a drain, which sends the water into the engine block. From there it passes into the cylinder heads, and drains back into the radiator for the process to repeat itself.