How to Test and Replace a Radiator Fan Motor

A malfunction in the radiator fan system can quickly cause your car to overheat on a hot summer day. There are a few things that can cause the fans to stop working, and you'll have to spend a little time trying to figure out what is wrong. Here is how you can check to see whether your fan motor is working and how you can replace it with a new one.

Checking Fan Motor

One of the simplest ways to check a fan motor is to supply a direct source of energy to it to see if the fan spins around.  You'll need a battery (you can use your car battery) and two wires. You will use the wires to connect the battery to the electric prongs inside the harness. These prongs hold the wires connecting the motor to the car's electrical system.

You'll want to have alligator clips on both sides of the pieces of wire. Connect one end of the wire to the negative terminal on the battery, and clip the other end to a prong inside the harness. Connect the other alligator clip to the positive terminal on the battery and touch the other end to the other prong in the harness. If the fan doesn't spin, you need a new motor.

Replacing Motor

You need to remove the bracket the fan is attached to in order to replace the motor. Most brackets have a couple of bolts at the corner of the bracket, but some also have a couple of bolts at the bottom of the bracket. In some cars, you can simply unscrew the nuts to the brackets and lift the bracket out of the engine compartment.

Other cars can be more complicated, and you'll have to remover radiator lines, reservoirs, and other parts. Make sure you keep track of what you are removing and how to put it back place so you don't get confused later on when you are trying to reconnect everything

Once the bracket and fan have been taken out of the engine compartment, remove the center cap in the middle of the fan blade (the cap keeps the fan on the shaft), and slide the fan up and off of the shaft. This will give you access to the screws under the fan blade that holds the motor onto the bracket. Remove the screws and detach the motor from the bracket.

Make sure the new fan motor is identical to the old one. The motors need to have the same casing size, shaft size, mounting holes, and electrical connectors.

Place the new motor against the bracket and hand-tighten the screws to hold the motor onto the bracket before tightening each screw with a screwdriver.

Place the fan blade back down the shaft and screw the cap back on.

Reconnect the bracket to the motor mount, then retest the motor with the battery to make sure the fans blades start spinning. If you still have problems, it might be best to have your car inspected by an auto repair shop like Two Square Auto Repair Ltd - German Car Specialist.