When the engine runs cold it is inefficient, pollution is at its maximum because of the need for rich fuel mixtures and engine wear is high due to friction. The engine is designed to be most efficient when running at its optimum temperature.

The job of the Engine Fan is to accommodate the transfer of heat from the engine and maintain the optimum operating temperature.In order to keep the engine cool, air must pass through the radiator core. When the vehicle is moving this is not a problem, but when the car is stationary assistance is needed. The cooling engine fan provides this.

There are a number of types of fans, fixed, viscous and the most common type the electric engine fan.
The fixed fan has a set of blades attached to the water pump drive pulley, which rotate at the same speed as the pump.