 A pressure regulator also acts as a bypass in case of a blockage in the cooler.A centrifugal pump sends coolant around the external rotor jacketing but via an intricate path in an attempt to even out the massive thermal stresses.Liquid enters at the point of highest temperatures (ignition), passing from the right side to the left, and then makes a 180° turn, returning to the right side and passing near the exhaust port.