What does the strain pulley do?
A travel belt tensioner is a pulley mounted on a spring device or adjustable pivot point that is employed to keep tension on the engine belts. … Both are used to keeptension on the engine serpentine belts in order that they can travel the many engine accessories.
How do you adapt a tensioner pulley?
Transform the adjustment bolt privately, top or bottom of the pulley counterclockwise with the ratchet and socket before accessory 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 could cause power loss and damage 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 wear out, causing noise and warmth. Pulleys are usually manufactured from either plastic or metal, so examine the pulley itself for any damage aswell. At O’Reilly Automotive Parts, we have tensioner pulleys designed for many vehicle models.
The computerized pulley tensioner comes with an internal spring-loaded mechanism that keeps the serpentine belt under constant tension. Its design allows it to keep the serpentine belt taut, so that the other item pulleys rotate at the same rpm (revolutions per minute) while under the same secure pressure. Tensioner pulleys may also absorb gentle shock loads that happen when the air conditioning unit cuts on and off. As a regularly rotating component, the pulley tensioner can provide off some warning signs 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,” as time passes 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 position in the adjustment pressure. Without the proper stress, the belt can slide.
Debris Contamination
Rocks, gravel and other highway debris can be thrown up into the tensioner pulley grooves and jam the device. This can allow the serpentine belt to slip on the tensioner pulley and burn. Overheated pulley temperature results, and eventually the serpentine belt will melt and snap off.
Pulley Tensioner Spring
The pulley tensioner spring inside the housing may become weak from age and repeated exposure to heat. This causes the belt to flutter and skip instead of maintaining a constant pressure on the pulley. Symptoms of a weak spring show as glazing on the underside of the serpentine belt, with an intermittent flickering of the dashboard’s charging light indicator. Squealing or squeaking will be listened to 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. Bad bearings trigger an audible growling noise. The external ends of the serpentine belt will fray and stretch out the belt. At some point the rubber belt grooves flatten out and cause major slippage. An excessively wobbling pulley can throw the belt off, leading to all the gadgets to quit functioning.
Lever Arm Freeplay
Some tensioner pulleys have markings on the casing that indicate the utmost 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 an extended, straightedge ruler against the face of the tensioner pulley, and flushing it against another item pulley, can measure the angle. Any off-angle measurement indicates put on shaft bearings in the pulley casing.
Serpentine Belt Noise
A moderately donned serpentine belt produces a constant squeaking noise during engine idle. Belts which have worn severely task a loud chirping or squealing audio. The cause items to a glazed, worn or cracked belt. Dry or partially frozen tensioner pulley bearings can cause such sounds by wearing out the belt prematurely.
Lever Arm Oscillation
A lever arm that repeatedly oscillates back and forth during idle or higher speeds means the the inside damper mechanism in the tensioner pulley has weakened or broken. This causes sporadic tension pressure on the belt and can manifest itself with intermittent chirping noises.