Why Does My Serpentine Belt Make Noise? (Cause and Fix)

The Serpentine Belt is responsible for running essential functions of your vehicle. However, a bad serpentine belt can cause costly damage to your vehicle. It can disable the power steering, air-conditioning unit, water pump, or even the alternator. Hence, if your serpentine belt is making noise, it’s bad news for you.

So, why does my serpentine belt make noise? Well, your serpentine belt can make squeaking noise for several reasons. A worn out or dry belt, damaged pulley or belt tensioner, misaligned belt, or cold weather can be responsible for the noise you are hearing. In any case, it would be wise to take care of the annoying noise as early as possible.

So, here we will find out the causes behind a noisy serpentine belt, and fix it easily following our step by step guide. Let’s dive in.

Why Does Serpentine Belt Make Noise? Common Causes

You already know that a failed serpentine belt can disable important engine components like the alternator and power steering. If you hear noise from the serpentine belt, it is a sign that it can fail.

The noise of the serpentine belt comes from the front of your vehicle. You may hear the squeaking sound of the belt louder when you accelerate your vehicle, or make a U-turn. If you hear a noise from the front of your vehicle, and you feel it is difficult to use the power steering, then you assume that sound is coming from the serpentine belt.

Well, as it is obvious that your serpentine belt is making noise, let’s learn the common causes behind it right away.

Worn Out or Dry Belt

Like any other truck part, a serpentine belt can be worn out over time. A worn out serpentine belt makes noise, and it can fail at any time. It generally lasts around 70,000 miles, a good quality serpentine belt. If you have crossed this range, maybe the belt is worn out. In that case, you need to replace it with a new one; that should fix the noise problem. We will guide you to replace a serpentine belt below in this article.

Again, a dry serpentine belt can make noise. Excessive heat from the engine can dry out the belt. If your belt is a dry one, you may notice tears and cracks on it. So, you can open your hood and look out for cracks. If it is a dry serpentine belt, replacing it may fix the noise you are hearing.

Damaged Pulley or Belt Tensioner

A serpentine belt can make noise due to a damaged pulley or belt tensioner. The belt system consists of pulleys and belt tensioner. The spinning pulleys and tensioner hold the serpentine belt while it spins and functions. Hence, a good serpentine belt can make noise because of a damaged pulley or belt tensioner.

The belt tensioner applies tension, which holds the belt. In case of a damaged pulley or belt tensioner, you need to repair or replace them by taking professional help.

Misaligned Belt

A serpentine belt needs to be aligned properly with the pulley grooves and tensioner. You can hear the belt noise because of a misaligned belt on the pulleys and tensioner. 

It can happen mostly in the case of a replacement. If you replaced a serpentine belt by yourself recently, chances are that you may have misaligned it while replacing. In that case, we recommend you should call for professional help and check your serpentine belt’s status.

Cold Weather  

Colder weather does have an effect on the serpentine belt. Your serpentine belt can make noise due to colder weather. In that case, you may notice the noise louder in the cold morning. But when the day gets hotter and the engine runs, the noise may become less.

Engine Antifreeze

The Engine Antifreeze is a liquid that regulates engine heat. It is also known as Engine Coolant liquid. In extreme cold temperatures, the engine system pumps the antifreeze to keep the engine functioning.  

But if it leaks, this antifreeze fluid can damage the serpentine belt instantly. So, due to a leaked engine coolant, your serpentine belt can make noise being damaged. In that case, we recommend you to call for professional help to check the coolant system and replace the serpentine belt.

How To Fix Serpentine Belt Noise? Step by Step Guide

Your serpentine belt can make noise for several reasons. To fix this noise problem, you need to identify it first, and then fix it.

We mentioned that worn out, damaged, or dry serpentine belts can make noise and damage your vehicle. So, replacing that bad belt will fix the problem. In the case of a bad pulley or tensioner, you need to replace them. We recommend you call for a skilled mechanic to do that for you.

Hence, here we guide you to fix the serpentine belt noise problem by replacing it with a new one. Let’s get ready to do this DIY following our step by step guide.

Step 1 – Tools

Replacing a damaged serpentine belt is an easy fix. So, you don’t need too many tools or heavy stuff. To relieve the auto tensioner that holds the serpentine belt firmly, you need to use a drive ratchet and socket. That’s all. 

Though it’s an easy fix, it can be tricky. So, follow our step by step guide carefully to get it right.

Step 2 – Open the Hood and Disconnect Battery 

To begin, you need to open the hood and reach the serpentine belt. It is always wise to disconnect the battery before you do automotive work. So, disconnect the battery connection by removing cables from the negative terminal. It should ensure your safety.

Step 3 – Locate the Serpentine Belt

In this step, you need to reach your serpentine belt by locating it. The belt’s location will depend on the location of the engine of your vehicle. It should be near the engine bay. You can also check out the manual to know its exact location.

Now you have to reach the serpentine belt by removing any part necessary. So, remove any part carefully and reach the belt.

Step 4 – Check the Belt’s Status

As you have reached the belt, now you check the condition of it. Look for any crack or tear on the belt’s surface. Check if it is worn out and dry. Check out carefully for any damage that may cause the serpentine belt noise you are hearing.

If you notice that the belt is damaged, it’s time to replace the belt with a new one. If you think the belt is alright, then maybe something else is faulty, like the pulley or belt tensioner. You should call a skilled mechanic to pinpoint the exact problem.

Anyway, let’s proceed to replace your damaged serpentine belt.

Step 5 – Note the Belt Route

The serpentine belt routes around different pulleys and a belt tensioner like a snake; that is why it is called the serpentine belt.

Before removing the belt, you have to note the belt’s route, so that it may help when you put in a new one. You should find the routing diagram at the engine’s bay. Or you can check out the manual for the routing diagram. Anyway, you can also draw the belt’s route in your notebook or take a photo using your smartphone.

Step 6 – Relieve the Tension

Now you have to relieve the tension off the belt. The serpentine belt stays firmly onto the pulleys because of the tension. So, relieving tension will help you to remove the belt easily.

The system uses tension by a belt tensioner pulley. Locate the belt tensioner pulley to relieve the tension it puts. This tensioner pulley either has a hole or a bolt.

Use a half inch ratchet to insert into the hole. Or if it has a bolt, use a socket over it. Now twist to untie and it will relieve the tension off the belt. The serpentine belt will come loose.

Some vehicles do not have the belt tensioner. They use the alternator bracket to put tension on the serpentine belt. In that case, remove the two bolts you can find on the alternator bracket. When you remove the bolts, it will push the alternator towards the engine, and that will relieve the tension.

Step 7 – Remove the Serpentine Belt 

As the belt has come loose, you can remove it out of the pulleys. First, remove it from the tensioner pulley, and then from all the pulleys.

As the belt is damaged, look for debris and remove them neat and clean.

Step 8 – Route the New Belt Correctly

Now you have to install a new belt. Put the new belt correctly on the pulleys following the same route as before. You can check the belt route diagram, or the photo you took to check the belt’s route. Run the belt through the route so that the belt sits on the pulley grooves firmly.

Step 9 – Apply Tension on the Belt

Lastly, you have to put the tension back on the serpentine belt. To do this, you need to run it over the auto tensioner pulley.

Use the same ratchet or socket to twist and loosen the auto tensioner pulley, hold it this way and use the other hand to  run the belt over it. Once the serpentine belt is in the right place, release the auto tensioner to apply tension on the belt.

Here you go; now you successfully replaced the serpentine belt. Hopefully, the serpentine belt noise is now solved. Put back on everything, connect the battery connection and close the hood. Enjoy your ride.


Serpentine belt can make annoyingly squeaking noises when you accelerate your vehicle or make a U-turn. The belt can make noise for several reasons. This noise is the sign of a bad belt which you should replace as early as possible. A bad belt can fail at any time, causing costly damages.

Worn out or dry belt, damaged pulley or auto tensioner, cold weather, coolant leakage, or misaligned belt placement can cause the serpentine belt to make noise.

As you have read this far, hopefully now you can replace the noisy serpentine belt on your own. Anyway, if you are not good at doing automotive projects, you can always call for a skilled mechanic to help you fix the serpentine belt noise.

See Also: Can You Drive Without a Serpentine Belt?

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