5 COMMON SYMPTOMS OF A BAD PULLEY -

In this article, you’ll see the most common symptoms of a bad pulley.

Due to the pulley being constantly under pressure and strain from the serpentine belt, over time, material fatigue appears, and the pulley gets damaged.

Mostly, problems start when the grooves on the pulley get chipped or deformed.

This article applies to problems with all the pulleys driven by the serpentine belt, and hopefully, it will help you notice the problem on time.

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SYMPTOMS OF A BAD PULLEY

1. THE SERPENTINE BELT WEARS OUT PREMATURELY

If you have to change the serpentine belt very often, like in half of its normal service life, it’s almost certain that one of the pulleys is damaged. It is the most definitive of all the symptoms of a bad pulley.

Besides this, you’ll notice that soon after you replace a new serpentine belt, it again becomes frayed on the edges, torn, and worn out.

For more information about the serpentine belt problem, click here.

2. A BURNING SMELL IS COMING FROM THE ENGINE BAY

Another symptom you may notice is a smell of a burning and scorched serpentine belt coming from the engine bay.

A bad pulley will damage the belt, which will cause it to slip. Slipping causes friction, and this produces the burning smell.

With a bad pulley problem, the smell casually appears, but with a badly damaged pulley, it will be present all the time.

3. THUMPING AND SQUEALING SOUND

Besides the damaged belt, you may also notice sounds coming from the engine bay and serpentine belt.

Besides the casual squealing, whistling, and later screeching sound caused by a slipping belt, you may also notice an unusual, vague thumping sound.

The thumping sound is, for instance, characteristic of a bad crankshaft pulley. In this case, finding the problem is very hard since it mimics other car problems.

4. THE PULLEY FALLS APART

Next, you may notice that the pulley completely falls apart, causing the serpentine belt to slip off the pulleys.

This symptom mainly applies to the alternator pulley since almost all modern alternators have an overrunning alternator pulley.

Unlike the classical pulley, which is a single solid metal piece, this type of pulley features a bearing and a clutch-type mechanism.

Mostly due to material fatigue, the mechanism fails, and the pulley may seize or, as mentioned, completely fall apart.

5. APPLIANCES AND DEVICES DO NOT WORK

Finally, if you miss all of these symptoms of a bad pulley, you’ll eventually notice that some of the devices in your car are not working properly, mostly due to the serpentine belt slipping.

This, of course, applies to the devices that are driven by the serpentine belt.

The most obvious signs would be that the cooling from the AC system is weak, the alternator voltage and electric power in the car are fluctuating, the power steering may occasionally become stiff, and so on.

CONCLUSION

When you notice the first symptoms of a bad alternator pulley, immediately make an inspection of the pulleys before installing yet another serpentine belt.

Rotate the pulleys, check the grooves, and see if there is any play or resistance in them. This way, you can also see if there is a bad bearing, for instance, and maybe that’s causing problems, not the pulley.

From personal experience, the most problematic are the alternator and the crankshaft pulleys.

The main reason is that, in most cases, these pulleys have the biggest tension on them.