A squeaky fan belt can be really embarrassing and can leave you with a headache every morning on start up before leaving for work. Many cars have a single belt which run on a number of accessories like the alternator, air conditioning compressor, water pump and power steering pump. All of these are considered accessories to the engine since they don’t not drive power to the wheels.

This single belt is better known as a serpentine belt and is different from your timing chain or belt in which it won’t cause immediate damage to your engine if it breaks. If it does break:

  • Your alternator will no longer charge your battery causing your battery light to come on.
  • Your power steering pump will lose power which will make your steering hard to turn.
  • If your water pump runs on your serpentine belt then the temperature in your engine will start to rise and your car will start to overheat.

The reasons behind the squeaks on your car can be diagnosed as one of the following:


As with any belt the tension is one of the most important things. If there is too much tension it can put excess stress on the accessory bearings and the belt which will can cause the belt to stretch and fail prematurely.

If the tension is too low, the belt will wobble and won’t have enough friction to drive the pulleys it’s running on.  If this is the case, the engine belt will slip on the pulley causing the annoying squealing noise you hate.


Your fan belts tension is controlled by an auto belt tensioner which is a spring loaded arm with the pulley on it. This spring loaded pulley controls and makes sure your belt has the correct tension so that everything runs smoothly and quietly. If your engine belt seems loose, squeaks, or wobbles or flaps while your engine is running it’s possible the tensioner either has a worn out bearing or the spring has lost its ability to create the proper tension.

Pulley damage:

This squeaking noise can persist from a failing accessory like for instance your power steering pump which causes drag on the belt or has a wobbling pulley. If this is so then it can be a bad bearing and this can be one of the causes of the squeaky noise.

Damaged belt:

Lastly the belt itself can be the cause of the squeaky noise. The belt over time usually will get worn out but it can also become worn prematurely by any one of the above reasons and from excessive heat exposure. If you notice that the ribbed side of the belt is shiny and getting cracked, it is an indicator that it’s time to change the belt.


Having a small squeak in your car at the start which eventually goes away after some time of driving may not seem like such a big problem but over time it can turn into something detrimental. Our advice from a mechanical perspective is as the driver and owner of the car you should always check up any small noise on your car especially if it hasn’t been making the noise all along.

Be sure to always check up with us if you notice any noise or squeak on your car. Our team of professionals will help diagnose the source of the problem and give you the best solutions to making sure it is sorted out.

Be it here, on Facebook or if you come on down to the shop at 3 Groom Street Verulam, to enquire about anything we will always be happy to help any way possible.

Drop a comment on the post if it did offer some assistance and don’t forget to share because this information could help others around you as well.

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