The drive belt – also known as a serpentine belt – keeps important components of your car’s accessory system running smoothly. The power steering, air conditioning, and sometimes even the water pump, rely upon this belt to provide them with power. The drive belt can only perform its job, however, if proper tension is maintained on it.

With time, wear and tear can have a destructive effect on the automatic tensioner, impeding its ability to keep the serpentine belt tight enough. If the belt is too loose it could come free of its pulleys, which in turn affects the operations of the parts it’s connected to. If the drive belt is too tight it could put undue strain on the water pump bearings and other vital parts under the hood, shortening their lives.

If your drive belt is creating vibration, rattles, sticks, stops working, or the tensioner shows obvious cracks or looseness, it could need replacing. There are some things to take into account when selecting a new one:

  • Consider aftermarket parts: One advantage of an aftermarket automatic tensioner is that the weaknesses of some tensioners that have failed have prompted a reverse engineering of the part in order to tweak the problems. This has resulted in tensioners that are, in some cases, actually better than OEM.

  • Look for a tensioner with corrosion protection: Rust and decay can shorten your part’s life.

  • Check with your dealer about a warranty: Sometimes drive belt tensioners are covered under the powertrain warranty, which would save you a few bucks on the repair. While the average home mechanic can handle the job of replacing the drive belt tensioner, the job does require a couple of specialized tools. If you don’t want to invest the money in a set of tools that will rarely be used, go ahead and let a professional do the task for you.

YourMechanic supplies top-quality drive belt tensioners to our certified mobile technicians. We can also install a drive belt tensioner that you've purchased. Click here to get a quote and more information on drive belt tensioner replacement.

This article originally appeared on YourMechanic.com as How to Buy a Good Quality Drive Belt Tensioner and was authored by Valerie Johnston.


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