What does the tension pulley do?
A drive belt tensioner is a pulley mounted on a spring system or adjustable pivot point that can be used to keep tension on the engine belts. … Both are used to keeptension on the engine serpentine belts to ensure that they can drive the many engine accessories.
How do you change a tensioner pulley?
Change the adjustment bolt privately, 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 you know
A tensioner pulley courses the belt around the tensioner and allows the belt to spin as the tensioner maintains pressure against it. A failing tensioner pulley can cause power damage and harm to your belt-driven systems. You might 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 warmth. Pulleys are usually made of either plastic or steel, so verify the pulley itself for any damage aswell. At O’Reilly Auto Parts, we’ve tensioner pulleys available for many vehicle models.
The programmed pulley tensioner comes with an internal spring-loaded mechanism that keeps the serpentine belt under regular tension. Its design enables it to keep the serpentine belt taut, in order that the other item pulleys rotate at the same rpm (revolutions per minute) while beneath the same secure pressure. Tensioner pulleys can also absorb mild shock loads that happen when the air conditioning unit cuts on / off. As a regularly rotating aspect, the pulley tensioner can give off some warning signs before failure.
Rust and Corrosion
The pulley tensioner sits subjected to the elements at the front of the engine. Put through puddled water “splash-up,” with time the tensioner arm and pulley device can rust. Corrosion can freeze the automated tensioner device or corrode the shaft bearings, which will cause a frozen job in the adjustment pressure. Without the correct stress, the belt can slide.
Debris Contamination
Rocks, gravel and other highway debris could be thrown up into the tensioner pulley grooves and jam the system. This can allow the serpentine belt to slide on the tensioner pulley and burn up. Overheated pulley temperatures results, and finally the serpentine belt will melt and snap off.
Pulley Tensioner Spring
The pulley tensioner spring inside housing may become weak from age and repeated exposure to heat. This triggers the belt to flutter and skip instead of maintaining a constant strain on the pulley. Symptoms of a fragile spring demonstrate as glazing on the underside of the serpentine belt, with an intermittent flickering of the dashboard’s charging lumination indicator. Squealing or squeaking will always be heard at the belt site.
Pulley Wobble
If the 
tensioner pulley wobbles on its shaft, this means the inside shaft bearings have worn. This will cause a pulley misalignment. Terrible bearings cause an audible growling sound. The external ends of the serpentine belt will fray and extend the belt. Gradually the rubber belt grooves flatten out and trigger major slippage. An excessively wobbling pulley can toss the belt off, triggering all the equipment to quit functioning.
Lever Arm Freeplay
Some tensioner pulleys have markings on the casing that indicate the maximum selection that the pulley can travel. If the lever arm of the tensioner rides under or over 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 to the other accessory pulleys with a parallel alignment. Placing an extended, straightedge ruler against the face of the tensioner pulley, and then flushing it against another item pulley, can measure the angle. Any off-position measurement indicates worn shaft bearings in the pulley housing.
Serpentine Belt Noise
A moderately donned serpentine belt gives off a constant squeaking sound during engine idle. Belts which have worn severely project a loud chirping or squealing appear. The cause points to a glazed, worn or cracked belt. Dry or partially frozen tensioner pulley bearings can cause such sounds by deteriorating the belt prematurely.
Lever Arm Oscillation
A lever arm that repeatedly oscillates backwards and forwards during idle or higher speeds means the the within damper mechanism in the tensioner pulley has weakened or broken. This triggers sporadic tension strain on the belt and will manifest itself with intermittent chirping noises.