When the engine runs, the process generates a lot of heat. If the temperature is not regulated, the motor could fail and cause all sorts of damage to the car's many different parts. Every car is equipped with a cooling system that feeds antifreeze through pipes that wind around the engine to dissipate heat. There is also a fan located under the hood to draw cool air into the engine compartment. In most older vehicles and some newer ones, this fan is belt-driven.
In recent years, technological advancements have brought about electric cooling fans. This alternative reduces engine noise and improves fuel economy. A belt-driven fan uses some of the power generated by the engine, and it runs constantly, whereas an electric device may use sensors to activate the fan when temperatures creep up too high. Even though an electric fan provides advantages over older versions, the effect on the engine will be the same if it breaks down.
If your vehicle is struggling with overheating issues, the electric fan may be the source of the problem. First, you should inspect the cooling system for leaks or low coolant levels, as this is the primary cause of overheating. Once you've determined this is not the issue, you'll want to make sure the cooling fan is working properly. Consult your owner's manual to determine the whereabouts of its fan. Some vehicles have two - one blowing on the radiator and transmission reservoir and the other for the engine.
The first step is to check to see if the fan is running. To do this, put the car in park or neutral with the emergency brake on and leave the engine running. Pop the hood and watch to see if the blades are spinning. If they are not, wait a few minutes. Your car may be equipped with a temperature sensor that shuts the fan off periodically to save energy. You can also crank the air conditioner, which should turn the fan on right away. If the fan still doesn't start, chances are there is a problem with the electrical components.
The fuse is the easiest and first thing to check. Use the owner's manual to determine which fuse connects to the fan, pop it out and inspect it for damage. If the metal filament is unbroken, replace the fuse. This should solve the problem, but if not, you could be looking at a number of other issues. The wires may be damaged, there could be a defective coolant sensor or switch, the fan motor might be failing, the relays could be bad or the engine thermostat may be busted.
If the fan runs when you crank the A/C but struggles otherwise, the electric circuit is likely fine. When all the electrical components have checked out, chances are the motor is the source of the problem. To test a fan motor, you can use jumper wires to supply an outside source of electricity. The motor should run with about 12 volts, but if you hear unnatural noises or notice the fan blades aren't spinning as fast as they should, the motor could be on its way out. A failing or damaged fan motor will need to be replaced.
The final thing you can check is the fan itself. When the engine is off (and the motor has had a chance to cool down), manually spin the fan blades. If they offer any resistance at all, there may not be enough lubrication and the blades are unable to spin as fast as necessary.
If a cooling fan problem goes unaddressed, you'll likely find the air conditioner does not work properly. As time goes on, the engine will start to overheat and cause a slew of other mechanical problems.