What does the tension pulley do?
A travel belt tensioner is a pulley mounted on a spring system or adjustable pivot point that is utilized to keep tension on the engine belts. … Both are used to keeptension on the engine serpentine belts to ensure that they can drive the various engine accessories.
How do you change a tensioner pulley?
Convert the adjustment bolt on the side, top or bottom of the pulley counterclockwise with the ratchet and socket before equipment belt is loose enough to remove. Tighten the tensioner pulley by turning the adjustment bolt clockwise with the ratchet and socket before belt is tight.
How do you know
A tensioner pulley guides 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 may 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 manufactured from either plastic or metal, so verify the pulley itself for just about any damage aswell. At O’Reilly Automotive 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 frequent tension. Its design allows it to keep 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 may also absorb slight shock loads that happen when the air conditioning unit cuts on and off. As a continuously rotating element, the pulley tensioner can provide off some warning signs before failure.
Rust and Corrosion
The pulley tensioner sits exposed to the elements at the front of the engine. Put through puddled water “splash-up,” with time the tensioner arm and pulley mechanism can rust. Rust can freeze the automated tensioner device or rot the shaft bearings, that may cause a frozen job in the adjustment pressure. Without the proper stress, the belt can slide.
Debris Contamination
Rocks, gravel and other street debris can be thrown up in to the tensioner pulley grooves and jam the mechanism. This can allow the serpentine belt to slide on the tensioner pulley and shed. Overheated pulley heat results, and finally the serpentine belt will melt and snap off.
Pulley Tensioner Spring
The pulley tensioner spring within the housing can become weak from age and repeated contact with heat. This triggers the belt to flutter and skip rather than maintaining a constant strain on the pulley. Symptoms of a weak spring display as glazing on the underside of the serpentine belt, with an occasional flickering of the dashboard’s charging lumination indicator. 
Squealing or squeaking will become read at the belt area.
Pulley Wobble
If the tensioner pulley wobbles on its shaft, this means the inside shaft bearings have worn. This will cause a pulley misalignment. Awful bearings cause an audible growling noises. The external ends of the serpentine belt will fray and stretch the belt. At some point the rubberized belt grooves flatten out and cause important slippage. An excessively wobbling pulley can toss the belt off, leading to all the components to quit functioning.
Lever Arm Freeplay
Some tensioner pulleys possess markings on the casing that indicate the utmost 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 facial skin of the tensioner pulley, and flushing it against another accessory pulley, can gauge the angle. Any off-position measurement indicates worn shaft bearings in the pulley housing.
Serpentine Belt Noise
A moderately put on serpentine belt produces a constant squeaking noises during engine idle. Belts that contain worn severely job a loud chirping or squealing sound. The cause details to a glazed, worn or cracked belt. Dry 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 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 noises.