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All of your vehicle’s engine accessories, as well as their drive belts, need to be in tip-top shape for your vehicle to perform like it should.

Belts should be replaced whenever they show signs of wear. Be sure to check the condition of your belts every time you have a chance to look at them. If your belts are cracked or worn, replacement may be necessary.



What is a Balance Shaft Belt?

Your vehicle’s balance shaft reduces engine vibration as you drive. Without working balance shafts, some engines may ruin their motor mounts due to excess vibration.

Your balance shaft belt turns your engine’s balance shaft. Some engines use belts, but others use a chain to drive their balance shafts. Your engine may be equipped with more than one balance shaft. On some vehicles, one balance shaft is belt driven while the other is chain or even gear driven. Your balance shaft belt may run very close to your vehicle’s timing belt as well, making balance shaft belt maintenance even more important.

How do Balance Shaft Belts Work?

No engine is perfectly balanced. In the early days of internal combustion engines, uncontrollable vibrations literally rattled engines apart at their seams. Balance shafts were designed and installed to counteract and negate excessive engine vibration. Although most engines run well without their balance shaft belts installed, the extra vibration puts stress on other engine parts like motor mounts, bell housings, and even cooling line connections. Without balance shafts, your vehicle may become unstable as the engine shifts around under hard acceleration.

Because balance shaft belts are often mounted near timing belts, a broken balance shaft belt could easily take your timing belt out with it when it breaks. Many mechanics recommend replacing both components at the same time, especially when the difference in labor costs is minimal.

How are Balance Shaft Belts Made?

Balance shaft belts are made from reinforced rubber.

Why do Balance Shaft Belts Fail?

  • Like all rubber components, your vehicle’s belts are vulnerable to heat. Heat created by your vehicle’s engine eventually wears belts and other rubber components to their breaking points.
  • Think of your vehicle’s belts like a sponge. When your belts are new, they are saturated with fresh factory moisture. As they heat up, this moisture burns off.
  • Like other rubber components, such as cooling hoses, your balance shaft belts become brittle, crack, and break due to age.

What are the Symptoms of Balance Shaft Belt Failure?

  • Excessive engine vibration may be felt while driving.
  • Motor mounts may fail prematurely.
  • If a broken balance shaft belt takes out your timing belt, your engine may suffer severe damage.

What are the Consequences of Balance Shaft Belt Failure?

  • There’s an extremely good chance a broken balance shaft belt will also result in a broken timing belt. A broken timing belt often means expensive, time consuming repairs are necessary to make the vehicle run again.
  • Looking after your belts should be a part of your routine maintenance procedures. Failing belts are often easy to spot before they break and create a bigger problem.

If you have questions or concerns about balance shaft belts or any of your vehicle’s components, come into your local Pep Boys where we can answer any question, help you find any part, or perform any vehicle service you might need.