In IC engines, a lot of heat generates in the process of combustion that needs to be rejected to its surrounding. Unless that, temperature of engine body will go on increase, in result it may develop thermal stresses or may cross melting point of used metal. Engine alone can't reject much heat to the surrounding through process of conviction due to limited surface area,as the more heat rejecting surface area, the more heat rejected through process of conviction. To increase the heat rejection, cooling water system is incorporated