Many of the key components and systems of your vehicle are run or powered via a rubber belt that connects to the engine’s drive shaft. With the aid of pulleys, these belts drive the engine fan, water pump, air-conditioning compressor, power-steering system, and the alternator in most vehicles. The alternator is a very important component that provides electrical power and charges the battery while the engine is running.

There are V-belts and/or Serpentine belts that will run one or multiple systems in your vehicle. Once an engine is running the belt operates continuously. High under hood temperatures plus the constant flexing that belts do, ultimately wears out the belt. Eventually, even the best belt will break. When it does the systems and/or accessories that the belt runs will stop operating.

According to the National Car Care Council, 19% of the cars on the road today have a worn belt that should be replaced. That equates to almost to 1 in every 5 cars. According to research statistics the incidence of belt failure rises sharply after four years of operation in many vehicles.
An Automatic Belt Tensioner is a metal device with a pulley that attaches to the engine. It applies tensions to the belt by way of an internal spring device that comes into contact with the belt. For a belt to function properly, it needs to operate with tension. Proper tension keeps the belt in contact with the various components with just enough pressure so that it provides power and does not slip in the accessory’s pulley grooves yet not so much that the tension creates heat which can shorten the belt’s life.

Belts, pulleys and tensioners should be inspected on a regular basis, with each oil change performed on the vehicle. Some of the symptoms to look and listen for are:

  • Belt Cracking – 3 or more cracks in a 3” section means it is time to replace it.• Belt Squeaking or Squealing  – could be a belt, pulley or tensioner wearing.
  • Rust Bleed around a pulley or tensioner – recommend replacement it is wearing out.
  • Oscillation or excessive movement of belt – tensioner is not holding proper tension and needs replacement.

Replacing a belt, pulley or tensioner is a relatively simple or minor repair. But a failure can result in other damage at times and a breakdown can occur costing more time and money. To keep your vehicle in proper working order don’t be the 1 in 5 cars on the road with belts that need replaced, have them replaced when they show signs of wearing to reduce your chances of an unexpected occurrence.

Steve and Karen Johnston are owners of All About Automotive in Historic Downtown Gresham. If you have questions or comments, call them at 503-465-2926 or email them at [email protected]. Steve and Karen Johnston are owners of All About Automotive, providing auto repair and auto maintenance in Historic Downtown Gresham. If you have questions or comments, call them at 503-465-2926 or email them at [email protected], you can also visit our website at

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