Alternator Belt Squeal After Replacement

If your car is making a squealing noise, especially after getting your faulty 

alternator belt fixed at a local repair shop, you’re not alone. It can be pretty annoying to drive around with this screeching noise. The belt’s primary function is to pull the pulleys okayed at the front of your vehicle’s engine. If your alternator belt or any of these pulleys are defective or damaged, it can create a squeaky sound.

Though the irritating noise coming from the front of your vehicle dies down once your car gets heated up, it can be quite uncomfortable and annoying to keep driving with the noise.

You will come across numerous reasons why your alternator belt starts screeching once you get the belt replaced. Keep scrolling to know why these drive belts keep screeching and how to fix the issue to avoid embarrassment. 

Should You Drive Around With A Screeching Belt?

The irritating and screeching noise is a warning signal that your alternator belt is defective and it’s time to get it repaired or replaced soon. Once you start hearing the squeaky noise, it is quite safe to drive your vehicle around for a few days.

After which, it is advisable to get it inspected and fixed at a local repair shop to stay on the safe side and avoid unforeseen happenings. 

So, Is Your Alternator Belt Still Screeching After It Got Replaced? Here’s why? 

A defective alternator belt can make a high-pitched squeaky sound when starting the engine. Also, when you step on the accelerator and increase the speed suddenly, the whirring sound can become even higher. The screeching noise reaches a higher intensity, especially during the hot summer days and rainy weather. 

However, you would have to look out for symptoms and signs of a defective alternator belt as the warning lights will not blink on your dashboard even when it gets damaged. If the belt is still making these irritating noises even after you replaced it with a new one, it can be due to many reasons. These include:

1. Faulty Spring-loaded Tensioner:

The alternator belt operates with the help of a powerful spring. While the engine is running, the spring-loaded tensioner helps adjust the belt. In case the spring breaks or gets damaged, the tensioner will start bouncing back and forth.

This motion causes the drive belt to move irregularly. At times, the belt becomes loose, and your car starts making a screeching noise which is a common defect in most vehicles. 

How to fix it? Replacing or repairing the entire spring-loaded tensioner will be necessary if the spring is defective due to constant wear and tear. In some cases, the squeaky noise happens when the tension on the belt is extremely tight.

Loosening the tensioner will help resolve this issue. If it’s too loose, make sure to adjust the tension on the belt to stop the noise.

2. Misalignment of the Pulley or Belt:

As a car owner, you might be aware that your car is equipped with numerous pulleys linked together using an alternator belt. Each of the components in your vehicle and in the engine is driven with the help of the belt.

The alternator belt is connected to the serpentine belt, which is linked to the engine pulley to get the engine running constantly. 

Any misalignment in the pulley or belt can cause a screeching sound. Even after replacing the defective belt, if the pulley or the belt is not aligned properly in its grooves, the noise may persist.

Misalignment mostly happens when the bolt moves slightly in or out of the pulley grooves. 

How to fix it? To fix all sorts of misalignment of the pulleys and belts, You’ll first have to locate where the tension has built up in the adjustment bolt and decrease it. Spin the pulley either outwards or inwards to release the tension based on the specific situation.

Once done, adjust the belt’s position and turn the pulley outwards to provide the belt with the correct amount of tension required. After you achieve the right amount of tension, proceed to tighten the tension on the adjustment bolt.

2. Idler Pulley or Tensioner Bearing is Defective:

You come across certain rollers in some cars that do not hold anything once you remove the fan belt. These rollers are commonly known as idler pulley or tensioner bearings. These tensioner bearings are primarily found in vehicles designed with a single big belt. 

On top of that, it turns out the tensioner bearings are further equipped with a tiny bit of bearing for optimal rotation. Any failure in this small bearing will create a whirring or screeching sound that can irritate the ears.

It can be quite challenging to detect this squeaky noise coming. You will find numerous pulleys driven by belts that make the same screeching sound when it gets damaged or broken. 

To figure out where the screeching noise is coming from, you’ll have to use a stethoscope to ensure the tensioner bearing is the culprit. This is because similar squeaky noises are also produced by the following:

  • Defective steering pumps. 
  • Faulty water pump. 
  • Damaged alternator bearings. 
  • Bad AC compressor bearing. 

How to fix it? Once you have identified the tensioner bearing as the source of the screeching or whirring noise, this indicates the idler pulley has worn out or become damaged.

You will have to replace the defective bearing with a new one as soon as possible to stop the annoying noise. You will have to first remove the belt and replace the tensioner bearing with a new one. Once complete, do not forget to reinstall the belt back to its original position. 

Final Thoughts

When it comes to the proper functioning of your vehicle’s engine, you need to give adequate care and attention to the alternator belt. Any defect in the alternator belt can cause the engine system not to function properly, causing a screeching noise.

Though this annoying noise can be embarrassing, it is an indication that there is something wrong with your drive belt. Ensure to get it replaced and if the sound persists, inspect what went wrong and fix the issue as soon as possible. 

Liam Dare

As CEO of, my passion for the automotive world motivates me to build online businesses that provide information and entertainment to users. I am proud to contribute in a positive way to the automotive community.