Bad Alternator Pulley Symptoms (9 Things To Be Aware Of)

If you’re knowledgeable about car maintenance, then you must know to check the alternator if your car won’t start or if something’s wrong with the car’s electronics.

While the alternator does indeed have an impact on your car, there’s a part of the alternator called the pulley that may be to blame for your car trouble. Here’s what I found!

Bad Alternator Pulley Symptoms

1. Damaged Alternator Belt

One of the first indications of an alternator pulley issue is a damaged alternator belt.

Generally, the alternator belt or serpentine belt powers the engine’s accessories while the connected alternator pulley spins the alternator to generate this power.

However, the alternator belt may break over time due to excess heat being generated by the alternator pulley.

As such, this may be indicative of a problem with the alternator and pulley.

2. Damage To The Alternator

Aside from a damaged alternator belt, another symptom is obvious wear on the alternator pulley.

Generally, as the pulley spins against the belt, both the pulley and the belt will eventually deteriorate.

Because of this, the surface of the pulley may develop observable scoring lines because of contact with the belt.

When tension is lowered due to wear on the pulley and belt, the belt will finally slip.

3. Warning Light On Dashboard

In addition to my points above, warning lights about the battery or alternator may be a symptom of a bad alternator pulley.

Generally, a warning light in the shape of a car battery will appear on the dashboard if computer sensors detect a problem with the alternator.

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However, on some car models, the warning light may take the form of the word “GEN” or “ALT” to indicate that something is wrong with the car’s main power source.

As such, these may be signs of a problem with the alternator pulley.

4. Abnormal Noises

Sometimes, you may hear growling or whining noises before the alternator fails.

In this case, the alternator pulley normally rotates the alternator while the alternator belt drives the engine’s accessories.

However, a growling or whining noise will alert you to a problem if the pulley is out of alignment with the belt, incorrectly angled on the shaft, or the bearings and bushings are worn out.

As a result, a defective alternator pulley is likely to be to blame if you hear these noises emanating from your car.

5. Burning Smells

Burning Smells

In addition, a defective alternator pulley can also cause burning smells to come from the engine bay.

For instance, if it smells like burnt wires, the pulley is probably to blame for the alternator overheating or burning.

However, if the air smells like burnt rubber, the alternator belt may have ruptured due to the extreme heat generated by the alternator pulley.

Therefore, determining the cause of any burning smells coming from your car is best done as soon as you notice them.

6. Inconsistent Headlight Brightness

Inconsistent headlight brightness may also be an indicator of a faulty alternator pulley.

Typically, the alternator supplies the electricity required for the electrical components of your car to operate.

As a result, if the alternator in your automobile has a faulty pulley, an irregular electric charge may reach these devices, including your headlights.

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For instance, as you accelerate, your headlights may fade, but then grow bright again when you slow down your car.

So, this can be an indication of a faulty alternator pulley.

7. Car Electronics Not Working

Additionally, your car’s electrical accessories failing to work may point to problems with the alternator pulley.

For instance, if your car’s air conditioning system ceases to work, it may be a problem caused by the alternator pulley.

Moreover, the same is also valid for your car’s other electrical components, including heated or ventilated seats, as well as the power windows.

As such, these issues can therefore help you identify the alternator pulley as the root of the problem.

8. Car Not Starting

Aside from my points above, a bad alternator pulley may also be the reason your car dies soon after starting or fails to start altogether.

In this instance, even if your battery has enough power, your car might not start because the alternator may have been harmed by a malfunctioning pullet.

As a result, if your alternator pulley is damaged, your car may erratically fail to start.

9. Car Stalling

Along with failing to start, your car may have a bad alternator pulley if it frequently stalls.

In most cases, if the alternator is not able to give electricity to the battery, the battery won’t be able to supply enough energy to start the ignition of your car.

As a result, the engine may also stall because the alternator isn’t supplying the spark plugs with enough power to keep the engine running.

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Therefore, this may be an indication that your alternator isn’t working due to a bad pulley.

To know more, you can also read our posts on bad alternator relay symptoms, bad alternator fuse symptoms, and Chevy bad alternator symptoms


When you suspect the alternator pulley is damaged, there are a few warning indicators to watch out for, such as a dashboard warning light and odd sounds or odors.

A faulty alternator bearing may also cause considerable harm to the alternator, which could then affect the ignition system.

To remedy any concerns, it is crucial to have the alternator and pulley evaluated at a service center right away.

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