Do your engine belts squeal every time you start your vehicle? Or maybe the engine belts squeal every time you turn on your air conditioning or turn your steering wheel to get out of a parking space. Maybe your engine belts just chirp all the time regardless of how you’re driving. Having engine belts that squeal is definitely embarrassing and can make a great car feel like a jalopy, but it also can be dangerous to you and your vehicle. A squeaking or squealing engine belt indicates an issue, which means it won’t be long before it breaks. Then, you have a real problem.

If the belt that operates your power steering pump fails, your steering would suddenly become heavy and unpredictable possibly causing an accident. Similarly, if the belt brakes that run your engine’s water pump, it could quickly cause your engine to overheat which could cause severe engine damage. To learn how to avoid these dangers, join me in the garage!

Having healthy belts in your engine is important for the safe operation of your vehicle. To understand a little more about engine belts and how they work, visit a local mechanic or check out what Firestone has to say about engine belts. Whether your car has a single serpentine belt or multiple individual tensioned belts, the squealing could be caused by one of the following reasons.

Why Do My Engine Belts Squeal?

  • A worn belt
  • Improper belt tension

The engine belt or belts in your vehicle is used to transfer the rotational energy of your engine to power smaller accessories. Your engine belts usually drive your alternator, power steering pump, and air conditioning compressor. On many vehicles, the belt will also drive the water pump, the engine cooling fan, and even emissions-related air pumps. In order for things to work properly, the belt must be able to run smoothly over pulleys to work properly and quietly. If your engine belts squeal, it is because the belt is slipping on that pulley, either because the belt is worn or there is too much or too little tension.

Worn Belt

The rubber belt runs on metal pulleys, so it will wear out over time. You can check your vehicle’s owner’s manual to see if there is a recommended interval for changing your engine belt. But if there isn’t, we recommend changing the belt or belts every 60,000 to 100,000 miles. You can tell if your engine belt is getting worn by checking for 3 things:

  1. Frayed edges
  2. Glazed surface
  3. Cracked ribs

Frayed edges on your engine belt can indicate misaligned pulleys or a failing accessory, so be sure to check the accessories and their pulleys when replacing a belt with frayed edges. If your engine belt’s surface gets glazed for heat or slipping, it will become shiny and have less friction, which will cause it to slip and squeal. Similarly, if your engine belt has cracked ribs, or even a cracked back, it can slip on the pulleys due to a lack of friction and cause that terrible squealing noise.

Improper Belt Tension

If your belt tension is too loose or too tight it can cause squealing or squeaking. If your belt has an automatic belt tensioner, the only option is to replace that tensioner to try and get the proper tension on your belts. If your belts are manually tensioned, you can try increasing or decreasing the tension on the belts using the tensioning adjustment screws to see if that can quiet things down. You can get a belt tension gauge to help you know when you’re at the right tension when using a manual belt tensioner. But there is a wide range of acceptable tensions for these belts. So, oftentimes, checking the belt tension by hand and comparing it to the tension of a belt that is quiet can get you close enough. For more information on how to tension your engine belts, join me in the garage!