Belt Tensioner’s Crucial Role
Tensioner plays a crucial role in the Accessory Belt Drive System (ABDS). Its sole job is to apply the correct amount of tension on the serpentine belt as it transfers power from the crank to the accessories in the system. The average automatic belt tensioner will adjust tension on the belt over one billion times for every 100,000 vehicle miles. Internal components in the tensioner can fail, causing stress
on the belt and other accessory components, allowing the belt to slip.
A slipping belt is the worst thing that can happen to the ABDS because of the noise and heat generated by the slippage, along with pulley wear. Heat transferred by the belt, causes the grease to boil and premature failure of the bearing cage.
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Signs of Tensioner FailureThe first sign of tensioner failure is belt noise or squeal. Squealing, among other things, indicates the spring inside the tensioner has
lost its tensioning ability allowing the belt to slip. In addition to generating noise and creating heat for the bearings, the alternator may
also lose its ability to charge or the A/C to cool efficiently. The more loads applied by the accessories, the more the belt wants to slip. Hearing belt squeal and seeing glazing on the underside of the belt are good indicators that tension has been lost, and the tensioner, along with the belt, must be replaced.
The second sign of tensioner failure is internal pivot bushing wear which results in the tensioner arm moving away from its base. This separation is very difficult to see because the tensioner is firmly bolted to the engine...read more |
