Alternator Belt Squeal After Replacement (Causes & Solutions)

October 15, 2021

Replacing the alternator belt.

You just changed your alternator belt, but the screeching noise it makes is bothering you. Unfortunately, it may be very aggravating for you! Pulling numerous pulleys that are positioned in front of the car’s engine is the function of the belt. Are you curious as to what is causing your alternator belt to screech after it has been replaced? One or more factors may be to blame for the alternator belt squeaking.

In front of your vehicle, you will see a slew of pulleys. Through the mechanical force supplied to them by the serpentine belt, these pulleys perform their functions correctly. They are belt-driven components. The alternator belt makes squeaking noises whenever these pulleys or your drive belt are damaged or worn down. Even if the screeching sound in front of your vehicle fades away whenever the car is heated, it may be very irritating and uncomfortable if you are driving.

This article addresses several issues you may notice if your belt is squeaking and how to determine whether your alternator belt is failing.

Major Causes Why Your Alternator Belt Squeals After Replacement

A shoddy belt is impossible to overlook. Starting the engine will cause you to hear a high-pitched continuous screeching as soon as you turn it on. Furthermore, as you speed abruptly, the screeching becomes more severe. Rainy days and humid summer days bring out the screaming to a new level of intensity. You will want to keep an eye out for the indications and symptoms of a faulty belt since the check engine light will not come on when it fails.

In addition to the high-pitched scream, a failed or defective belt also varies in several glaring factors. They are as follows:

Faulty Hydraulic Belt Tensioner

Some vehicles use a hydraulic belt tensioner to keep the drive belt in place while driving. The tensioner behaves similarly to a spring-loaded tensioner in operation, with the shock absorber serving as the primary controller. The alternator belt may begin to scream if the hydraulic belt tensioner fails. It is particularly true if you are doing turns while driving. The majority of the squeals, on the other hand, will occur when the vehicle engine is running at idle. Belt tensioners like this one are common on Corolla and Matrix cars from Toyota.

To begin the repair process, you must first check the hydraulic belt tensioner to see whether it is loose or excessively tight. In order to avoid inflicting severe damage to the engine, you must use extreme caution while performing repairs or changing the hydraulic belt tensioner.

Tensioner Bearing Or Idler Pulley Not Functioning Properly

It has been observed that certain rollers do not retain anything after the fan belt has been removed from certain cars. Tensioner bearings are the technical term for what we have here. When referring to idler pullers, this is another name for them. They are often seen in cars with a single massive belt. 

Following that, the tensioner bearings guarantee that the belt turns in the proper direction. It is possible to hear a squeaking or whirring noise when the small bearings within the idler pulleys fail. If you hear this noise, you may not be able to tell where it is coming from.

Replacement of the tensioner or idler pulley bearing is required if one of these components has failed unexpectedly. The measures needed to complete this process are straightforward. First, remove the belt in replacing its idler pulley, and afterward, reinstall the belt.

Faulty Spring Loaded Tensioner

A powerful spring is responsible for the operation of the spring-loaded tensioner, which we discussed earlier in this article. When the vehicle is in motion, this is in charge of adjusting the alternator belt. Even though it is rare, a faulty spring in the tensioner may cause a back-and-forth motion. You will hear a screeching noise if this occurs, or the alternator belt will occasionally come loose.

Repair or replacement of the whole tensioner may be necessary if the spring-loaded tensioner has failed due to wear and tear. If the belt is too tight, loosen the tensioner. If it is too loose, tighten the tension on the belt again.

Misalignment Of The Belt or The Drive Pulley

Your vehicle is equipped with many pullers that are held in place by a drive belt. A belt drives almost every component of your vehicle. A serpentine belt links the alternator to a pulley on the engine, which allows it to run constantly. In this way, the alternator may spin in conjunction with the other belt-driven parts. A misplaced belt or pulley may result in squeaking even after you replace the alternator belt. To put it another way, this implies the belt and pulley grooves are not aligned up perfectly.

Fixing misaligned belts and pulleys requires first locating and loosening the tension adjustment bolt, which may be found on the belt’s tension adjustment bolt. In order to decrease tension, spin the pulley inwards now or outwards as per the situation. Afterward, adjust the belt’s placement and turn the pulley outwardly to make sure tension is provided. You may then tighten your tension adjustment bolt after you have achieved the desired level of tension.

Defective Belt

When you choose a low-quality alternator belt to change your old one, it may not have the power to drive the pulleys in your car. Pulleys may become jammed, or belts can exert too much effort, which results in squeaking or whistling noise. Possibly, the newly installed belt is either loose or tight, which is causing the issue. In this case, if you installed an inexpensive and subpar alternator belt in your vehicle, you will need to replace it with a high-quality one.

What Happens If The Alternator Belt Is Too Loose?

You will have a slew of problems with your vehicle if you leave the alternator belt loosen while driving. Eventually, y our alternator will not function correctly, resulting in the alternator charging at a low level and inevitably shutting down completely. If your vehicle is driven for a longer duration with a loosened alternator belt, it will eventually stop itself due to battery depletion. You should always make sure your alternator belt is well-tightened but not too tight since it will have its own consequences.

Is It A Bad Idea To Drive With A Squeaky Belt In Your Car?

Squeaking is an indication that your belt needs to be replaced or repaired. Driven safely for the first several days after hearing the screeching noise, you may not be in danger, but you need to replace the belt or bring it to the repair shop for further inspection.

What Can I Do To Prevent My Aux Belt From Screeching?

Make no mistake! The auxiliary belt is interchangeable with a drive belt, alternator belt, or fan belt. If your aux belt continues to screech despite your efforts, it is time to figure out what is wrong and do something about it. A misaligned belt, a damaged belt, or faulty pulleys may all cause a screeching aux bet. Find the source of the noise and make the necessary repairs or adjustments.