What does the tension pulley do?
A travel belt tensioner is a pulley mounted on a spring mechanism 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 to ensure that they can drive the many engine accessories.

How do you modify a tensioner pulley?
Transform the adjustment bolt privately, top or bottom of the pulley counterclockwise with the ratchet and socket until the item 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 while the tensioner maintains pressure against it. A failing tensioner pulley could cause power loss and damage to your belt-driven systems. You might have a failing tensioner pulley in the event that you hear any squeaking or squealing under the hood. Bearings on the pulley can degrade, causing noise and heat. Pulleys are usually manufactured from either plastic or metallic, so check the pulley itself for any damage aswell. At O’Reilly Car Parts, we have tensioner pulleys designed for many vehicle models.

The programmed pulley tensioner has an internal spring-loaded mechanism that keeps the serpentine belt under continuous tension. Its design permits it to keep carefully the serpentine belt taut, to ensure that the other equipment pulleys rotate at the same rpm (revolutions each and every minute) while under the same secure pressure. Tensioner pulleys can also absorb gentle shock loads that happen when the air conditioning unit cuts on / off. As a continuously rotating element, the pulley tensioner can give off some indicators before failure.

Rust and Corrosion
The pulley tensioner sits exposed to the elements at the front end of the engine. Put through puddled water “splash-up,” as time passes the tensioner arm and pulley device can rust. Corrosion can freeze the computerized tensioner device or corrode the shaft bearings, that may cause a frozen posture in the adjustment pressure. Without the correct stress, the belt can slip.
Debris Contamination
Rocks, gravel and other road debris could be thrown up in to the tensioner pulley grooves and jam the system. This can permit the serpentine belt to slip on the tensioner pulley and burn off. 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 can become weak from age and repeated exposure to heat. This triggers the belt to flutter and skip instead of maintaining a constant pressure on the pulley. Symptoms of a poor spring present 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 interior shaft bearings have worn. This may cause a pulley misalignment. Undesirable bearings trigger an audible growling sound. The external ends of the serpentine belt will fray and extend the belt. At some point the rubberized belt grooves flatten out and trigger significant slippage. An excessively wobbling pulley can toss the belt off, leading to all the add-ons to quit functioning.
Lever Arm Freeplay
Some tensioner pulleys possess 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, 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 facial skin of the tensioner pulley, and then flushing it against another equipment pulley, can measure the angle. Any off-angle measurement indicates donned shaft bearings in the pulley housing.
Serpentine Belt Noise
A moderately worn serpentine belt gives off a constant squeaking noise during engine idle. Belts which may have worn severely task a loud chirping or squealing sound. The cause points to a glazed, worn or cracked belt. Dried out 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 backwards and forwards during idle or more 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 sounds.