Fan belts and how they work

Does your car sometimes make a loud squeaking sound in the morning as you start driving? After a short distance, the sound disappears, making you believe that everything is back to normal. Technically, the squeaking sound could be due to a bad or worn out fan belt.

Isaac Nalyongo, a mechanic, says fan belts, sometimes referred to as V-belts or drive belts are located in front of the engine and their primary purpose is to drive the alternator, steering pump, fun-belt steering, power steering, belt tensioner and the AC pump, where the main pulley is also fitted. Fan belts are easily seen and are made of rubber.

Some cars have two to four fan belts. However, there are cars such as Subarus made from 2008 upwards and the 2010 model Premios and their predecessors that have one fan belt, while some Land Cruisers have up to four.

“Fan belts are important. When one breaks, especially that which drives the alternator and steering pump, the battery will not charge and the steering wheel will be hard to turn. For cars where the fan belt drives everything, when it breaks, every other part that runs with it stops,” Nalyongo explains.

Attuned

A number of parts work closely with fan belts. One of them is the tensioner bearing, which can sometimes cause the belt to break when it gets stuck or absorbs dust. Similarly, the alternator can also break the belt since it uses the bearing. When the bearing makes noise, replace it before it eventually breaks the belt. The air conditioner pump also sometimes stops and breaks the belt. Even if the belt is genuine, sometimes it may be broken by the alternator, the AC pump or the steering pump.

“All these need to be checked often since they contribute to the running and longevity of the fan belt. To make sure the belt is safe, these parts must also be safe. When the belt starts to develop cracks, have it replaced since it may break without warning. Take your time to source for a genuine fan belt because there are many on the market that look good but break within a short time,” Nalyongo advises.

Cost

On average, a genuine fan belt lasts a minimum of one year. Alex Kadoli, a mechanic, says a genuine fan belt is bought from specific dealers or those that specialise in European cars such as Range Rovers.

“The cost of the fun belt determines how long it will last. If the cost of a fan belt is below Shs40,000, you are buying one that will last only a short while. Cheap things become expensive in the long run,” Kadoli advises.

Besides quality and price, sometimes the belt may be of good quality but when it was not well tensioned by the mechanic during service. It is supposed to be tight, not loose.

Fun belt maintenance

All fan belts are rubber and elastic. As you drive, they keep enlarging and you have to keep adjusting. If you hear a squeaking sound while turning, it means you need to stop and adjust your belt to make it tighter. To maintain your fan belt, listen to the engine and inspect it all the time. Sometimes it may not make noise but has cracks, an early warning sign that you need to have it replaced. 

Driving habits that damage fun belts

In automatic cars, when you accelerate harder and push the car to engage a shooting gear to give you the torque you need urgently, it means you are forcing and pushing the fan belt harder yet the change of engine motion has to be gradual to give you the speed you want. The abrupt change of engine motion as the car gains speed will in the long run affect the fan belt and reduce its longevity. With manual transmission cars, the damage to fan belts is minimised because speed comes with light gears that vehicles engage manually.

HOW CAN I TELL IF MY FAN BELT IS BAD?

1. Steering your vehicle becomes a wrestling match. As the fan belt continues to lose its grip and slip, it makes power steering increasingly difficult, as your car misses the help of the water pump, which also has responsibility for driving the power steering belt.

2. Dim lights. As the belt continues to lose its grip, it will struggle to turn the alternator, especially during a cold start. So, you may notice that the lights inside the car, and the headlights, go dim when you start your car or whenever there is an extra load on your battery.

3. Your car hits the “snooze” button when you try to start it. As your serpentine belt wears down, it has trouble turning the alternator belt consistently, which can lead to no-start problems. Sometimes, it gets so bad that it kills your battery, or causes the car to intermittently fail to start, even when the battery is charged up.

4. Your vehicle spikes a fever. As your fan belt or serpentine belt breaks down and frays, it will not be able to turn the water pump consistently, which slowly defeats the engine’s cooling systems and causes the temperature to rise more than it should. At first, I will only be a few degrees and you might just notice offhand that your temp gauge is up a few degrees more than normal. After a while, if the belt lets the water pump slide enough times, the engine will overheat.

5. Your serpentine belt is impersonating a snake in the grass. If you find your fan belt is no longer attached to your engine or is lying on the ground somewhere, that is definitely a sign that it is time to replace it.

- Source: axleaddict.com