5 Causes of Serpentine Belt Squealing Noise (When Cold or Accelerating)

Whenever your internal combustion engine is running, your serpentine belt is running too. The serpentine belt provides mechanical power to the power steering pump, air conditioning compressor, alternator, and many other important peripheral accessories.

If you ever start hearing strange noises coming from your engine area, then it might be due to your serpentine belt. Cold weather is notorious for making these noises much worse.

Whatever problem your serpentine belt is facing, colder temperatures can exacerbate them. As those problems get worse, the noises get louder and more annoying.

Of course, cold weather can cause squeaks and squeals to come from any number of components in your vehicle. If the serpentine belt is not directly making these noises, then the noises may be caused by one of the engine accessories.

These are the accessories in which the serpentine belt powers up by transmitting mechanical energy to the. If cold temperatures are making the serpentine belt’s job harder, then these other accessories may malfunction or start making strange noises themselves.

Top 5 Causes of Serpentine Belt Squealing

Cold winter weather is never a friend to your vehicle. If your wheel well suffers ice accumulation, then strange noises will follow. If you hear squeals, then it could be your engine belt or serpentine belt.

But in most cases, it will be your serpentine belt that is making these noises. They may even get worse as you step on the gas pedal to accelerate. Here are five of the most common reasons your serpentine belt is making noise when cold or accelerating.

1) Bad or Worn Tensioner

serpentine belt squealing

The serpentine belt is given the proper amount of tension by a device called a drive belt tensioner. The tensioner is basically a pulley connected to an adjustable pivot.

If you ever have a bad or worn-out tensioner, then it’ll affect the tension of your serpentine belt on the pulleys of the system. Your serpentine belt will become loose, resulting in strange noises when you accelerate.

2) Belt Misalignment

bad serpentine belt symptoms

Sometimes the serpentine belt might be in good condition, but it is simply misaligned. If your mechanic recently installed a new serpentine belt in your system and you still notice annoying sounds, then they probably didn’t do a good job of aligning the belt onto the pulleys properly.

In other cases, a worn-out tensioner could cause the misalignment if the belt is loose.

Read Also: Serpentine Belt vs. Timing Belt – What’s the Difference?

3) Belt is Worn Out

cracks in serpentine belt

Serpentine belts used to last about 50,000 miles in older vehicles. However, the newer serpentine belts are made from highly durable synthetic rubber. The scientific name of this material is ethylene propylene diene terpolymer or EPDM for short.

If your serpentine belt is made from EPDM, then it can last up to 100,000 miles. After that, you should notice the ribs of the belt getting worn out. This will cause it to move poorly over the pulleys, creating all kinds of noises. Cold weather can also deteriorate the belt faster too.

See Also: 7 Timing Belt Replacement Tips (for DIY Mechanics)

4) Idler Pulley Misalignment

Your serpentine belt is not the only component which can become misaligned. Aside from the pulley of your drive belt tensioner, the idler pulley can cause the serpentine belt to make noises too.

The idler pulley is another one of the pulleys which help keep the serpentine belt moving. It helps move the other engine accessories too. If the idler pulley is misaligned, then the serpentine belt will make noise.

5) Slippage

drive belt slippage

If you don’t take care of the loose serpentine belt problem quickly, then the entire belt could slip off the pulleys. This will cause the most noise because all your important engine accessories will suddenly stop functioning at the same time.


7 thoughts on “5 Causes of Serpentine Belt Squealing Noise (When Cold or Accelerating)”

  1. Mine is also making a loud noise when I turn the car on with the remote start and the heat is on, if I turn the heat off it stops. Is it dangerous to drive if I don’t get it fixed right away?

    • Does this noise ever go away? Are you referring to a cold start where in order to get the engine and catalytic converters warm faster the ecu adjusts the air/fuel ratio to run rich which burns more fuel and the exhaust will make more deeper grumbles. It really does roar to life when cold if thats what you mean


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