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.
If you are working on a vehicle with a mechanical fan you may need to remove the fan shroud to get the fan out by loosening a couple of nuts. Normally the fan and clutch are removed from the waterpump or fan pulley as a unit by undoing one large bolt (which may be reverse threaded) or several bolts. If the pulley tries to rotate while removing the nut you can try using a hammer to tap the wrench (simulating an impact gun) or holding the pulley with a strap wrench, but you may need to purchase a special tool to keep it from moving. Once the fan blades and clutch are removed from the vehicle they can normally be separated by removing a few more nuts. Sometimes the mechanical fan needs to be removed to change your belts, if this is the case this may be a good time to install a replacement. Follow these steps in reverse to re-install the new fan or fan clutch.
If you are working on a vehicle with an electric fan, normally the fan and shroud are removed as one component. The shroud is normally attached to the radiator or brackets using nuts and bolts, clips, or a combination of the two. With the nuts and bolts undone you may need to tilt the fan and shroud assembly to detach any clips. The fan and shroud should then simply pull out of the vehicle. Installation should be the reverse as removal.
Once you have reinstalled the new fan ensure that all nuts and bolts are properly torqued and make sure that the fan blades won't rub or come into contact with anything. Carefully reconnect any wiring or harnesses that you removed and reposition everything, again making sure the fan is clear of any obstructions. Once everything is back in place reconnect the negative battery cable and start the car. Let the car get to operating temperature and watch the fan to make sure that it works as expected.