The drive belt tensioner in your car is a small component that works in conjunction with the serpentine belt to ensure that everything in your engine works as it should. From time to time, the tensioner should be checked to ensure that it’s set correctly. Your mechanic can do this for you as part of your routine maintenance. On occasion, it may have to be replaced.

What does the belt tensioner do?

In your engine compartment, the serpentine belt winds around various components, including your alternator, power steering pump, water pump, air conditioning compressor, and more. The tensioner ensures that the belt delivers enough tension while you’re driving, so that the belt can move the various pulleys that drive the engine components.

The parts

The drive belt tension is made up of four main parts – the base, tensioner arm, spring and pulley. The base holds the other parts, and the spring keeps the belt pulled tight. The pulley is what facilitates movement of the belt. The tensioner arm is found on the bottom of the tensioner, and if you press on it, it will work against the spring, delivering enough slack so that you can adjust or remove the belt.

Adjusting the belt tensioner

Adjusting the drive belt tensioner is not something you should attempt to do yourself – leave this job up to a pro. The serpentine belt is absolutely vital to the function of your vehicle, and if you end up with a belt problem due to an improperly adjusted tensioner, the damage can be catastrophic.

This article originally appeared on YourMechanic.com as How Belt Tensioners Work and was authored by Valerie Johnston.


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