Your vehicle's belt tensioner is not a part that you commonly think of when you have vehicle problems. However, a malfunctioning belt tensioner can cause a variety of problems for your vehicle. There are several symptoms you should be aware of if you suspect that your vehicle has a bad or malfunctioning belt tensioner.
Your belt tensioner's primary job is to keep your vehicle's serpentine belts tight. When the belts are not tight while turning, they will begin to slip. If you watch your vehicle's serpentine belt while the vehicle is running, you may notice that the belt does not appear to be tight on the pulleys. Also, your battery may go dead because the alternator is not receiving enough power.
Loose belts tend to squeal. A squealing belt is a loud, unpleasant noise that will quickly draw your attention to the problem, though many people make the mistake of replacing the belt without looking at the tensioner. However, if the tensioner is to blame for the squeal, then it will not be long before the new belt begins to squeal as well.
If the belt tensioner exerts too much pressure on the pulleys or causes a vibration, it can affect the pulleys' ability to work and even cause them to wear out or break. If you have problems with your pulleys breaking or malfunctioning, it may be wise to replace the belt tensioner as well.