What does the strain pulley do?
A drive belt tensioner is a pulley mounted on a spring system or adjustable pivot point that is employed to keep tension on the engine belts. … Both are being used to keeptension on the engine serpentine belts in order that they can drive the various engine accessories.
How do you change a tensioner pulley?
Change the adjustment bolt on the side, top or bottom of the pulley counterclockwise with the ratchet and socket until the accessory belt is loose enough to eliminate. Tighten the tensioner pulley by turning the adjustment bolt clockwise with the ratchet and socket until the belt is tight.
How do I know
A tensioner pulley manuals the belt around the tensioner and allows the belt to spin while the tensioner maintains pressure against it. A failing tensioner pulley can cause power loss and harm to your belt-driven systems. You could have a failing tensioner pulley if you hear any squeaking or squealing under the hood. Bearings on the pulley can wear out, causing noise and temperature. Pulleys are usually made of either plastic or metal, so examine the pulley itself for just about any damage as well. At O’Reilly Car Parts, we have tensioner pulleys available for many vehicle models.
The programmed pulley tensioner comes with an internal spring-loaded mechanism that keeps the serpentine belt under constant tension. Its design enables it to keep carefully the serpentine belt taut, to ensure that the other equipment pulleys rotate at the same rpm (revolutions per minute) while beneath the same safe pressure. Tensioner pulleys can also absorb mild shock loads that happen when the air conditioner cuts on and off. As a frequently rotating part, the pulley tensioner can provide off some indicators before failure.
Rust and Corrosion
The pulley tensioner sits subjected to the elements at the front of the engine. Subjected to puddled water “splash-up,” with time the tensioner arm and pulley device can rust. Corrosion can freeze the automatic tensioner device or corrode the shaft bearings, which will cause a frozen posture in the adjustment pressure. Without the correct pressure, the belt can slide.
Debris Contamination
Rocks, gravel and other road debris can be thrown up into the tensioner pulley grooves and jam the system. This can permit the serpentine belt to slide on the tensioner pulley and lose. Overheated pulley temperatures results, and eventually the serpentine belt will melt and snap off.
Pulley Tensioner Spring
The pulley tensioner spring inside the housing can become weak from age and repeated contact with heat. This causes the belt to flutter and skip instead of maintaining a constant pressure on the pulley. Symptoms of a poor spring demonstrate as glazing on the underside of the serpentine belt, with an intermittent flickering of the dashboard’s charging mild indicator. Squealing or squeaking will be been told at the belt position.
Pulley Wobble
If the tensioner pulley wobbles on its shaft, it means the inside shaft bearings have worn. This may cause a pulley misalignment. Awful bearings trigger an audible growling noises. The external ends of the serpentine belt will fray and extend the belt. At some point 
the rubber belt grooves flatten out and trigger major slippage. An excessively wobbling pulley can throw the belt off, creating all the add-ons to quit functioning.
Lever Arm Freeplay
Some tensioner pulleys possess markings on the housing that indicate the maximum selection that the pulley can travel. If the lever arm of the tensioner rides under or higher the designated mark, this implies a stretched belt or a lever arm that has jammed in a single position.
Pulley Misaligment
The tensioner pulley face must match to the other accessory pulleys with a parallel alignment. Placing a long, straightedge ruler against the facial skin of the tensioner pulley, and then flushing it against another accessory pulley, can gauge the angle. Any off-angle measurement indicates put on shaft bearings in the pulley casing.
Serpentine Belt Noise
A moderately worn serpentine belt gives off a constant squeaking sound during engine idle. Belts which may have worn severely task a loud chirping or squealing appear. The cause factors to a glazed, put on or cracked belt. Dry or partially frozen tensioner pulley bearings can cause such noises by wearing out the belt prematurely.
Lever Arm Oscillation
A lever arm that repeatedly oscillates backwards and forwards during idle or more speeds means the the within damper mechanism in the tensioner pulley has weakened or broken. This triggers sporadic tension strain on the belt and can manifest itself with intermittent chirping sounds.