What does the strain pulley do?
A drive belt tensioner is a pulley mounted on a spring mechanism or adjustable pivot point that is used to keep tension on the engine belts. … Both are used to keeptension on the engine serpentine belts in order that they can travel the various engine accessories.
How do you adjust a tensioner pulley?
Change the adjustment bolt privately, top or bottom of the pulley counterclockwise with the ratchet and socket before 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 tutorials the belt around the tensioner and allows the belt to spin while the tensioner maintains pressure against it. A failing tensioner pulley could cause power damage and harm to your belt-driven devices. You could have a failing tensioner pulley if you hear any squeaking or squealing beneath the hood. Bearings on the pulley can degrade, causing noise and warmth. Pulleys are usually manufactured from either plastic or metallic, so verify the pulley itself for just about any damage aswell. At O’Reilly Vehicle Parts, we have tensioner pulleys designed for many vehicle models.
The automated pulley tensioner has an internal spring-loaded mechanism that keeps the serpentine belt under constant tension. Its design permits it to keep the serpentine belt taut, in order that the other equipment pulleys rotate at the same rpm (revolutions per minute) while under the same secure pressure. Tensioner pulleys may also absorb slight shock loads that happen when the air conditioning unit cuts on / off. As a continuously 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 end of the engine. Put through puddled water “splash-up,” with time the tensioner arm and pulley device can rust. Corrosion can freeze the computerized tensioner device or corrode the shaft bearings, which will cause a frozen situation in the adjustment pressure. Without the correct pressure, the belt can slide.
Debris Contamination
Rocks, gravel and other street debris could be thrown up in to the tensioner pulley grooves and jam the mechanism. This can allow the serpentine belt to slip on the tensioner pulley and lose. Overheated pulley heat range results, and finally the serpentine belt will melt and snap off.
Pulley Tensioner Spring
The pulley tensioner spring within the housing may become weak from age and repeated contact with heat. This causes the belt to flutter and skip rather than maintaining a constant strain on the pulley. Symptoms of a poor spring show as glazing on the underside of the serpentine belt, with an occasional flickering of the dashboard’s charging light indicator. Squealing or squeaking will become listened to at the belt site.
Pulley Wobble
If the tensioner pulley wobbles on its shaft, this means the inside shaft bearings have worn. This may cause a pulley misalignment. Terrible bearings cause an audible growling noise. The outer ends of the serpentine belt will fray and stretch the 
belt. Sooner or later the rubberized belt grooves flatten out and trigger main slippage. An excessively wobbling pulley can throw the belt off, causing all the components to quit functioning.
Lever Arm Freeplay
Some tensioner pulleys have 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, it indicates a stretched belt or a lever arm that has jammed in a single position.
Pulley Misaligment
The tensioner pulley face must match up to the other accessory pulleys with a parallel alignment. Placing an extended, straightedge ruler against the facial skin of the tensioner pulley, and then flushing it against another equipment pulley, can gauge the angle. Any off-position measurement indicates worn shaft bearings in the pulley casing.
Serpentine Belt Noise
A moderately worn serpentine belt gives off a constant squeaking noise during engine idle. Belts which have worn severely task a loud chirping or squealing appear. The cause factors to a glazed, donned or cracked belt. Dried out or partially frozen tensioner pulley bearings could cause such sounds by wearing out the belt prematurely.
Lever Arm Oscillation
A lever arm that repeatedly oscillates back and forth during idle or more speeds means the the within damper mechanism in the tensioner pulley has weakened or broken. This triggers sporadic tension pressure on the belt and will manifest itself with intermittent chirping sounds.