There is a Diesel Engine Fan offered by us which rotates, either driven by electric motors or from the engines crank shaft by a series of pulleys and belts. This fan blows cool ambient air through the radiator fins. The heat at the fins is transferred to the cool air, heating it up, taking the heat away from the engine. As a diesel engine runs, heat is generated during the combustion process. The Diesel Engine Fan is very effective and useful.