The radiator fan helps prevent the vehicle's engine from overheating, especially when the vehicle is idling or moving slowly. Before you learn how to replace the radiator fan, you should first ensure that it needs replacement. If your car uses a mechanical fan that is turned by a belt, the fan should turn whenever the engine is on. If the belt is broken or loose the fan won't turn properly. If the fan clutch is defective the fan might not turn fast enough, causing overheating problems, or the fan might turn too quickly, increasing fuel economy and potentially a loss in heat. If your car uses an electric fan it should cycle on and off depending on the temperature of the engine. If the fan never turns on it may be a burned fuse, bad wiring, or a defective fan motor.
Once you've determined that the fan needs to be replaced, the first step is to disconnect the negative battery cable. Disconnect any electrical wires running to the fan or fan clutch, and move any other hoses and wires out of the way.