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 being used to keeptension on the engine serpentine belts to ensure that they can travel the various engine accessories.
How do you adjust a tensioner pulley?
Flip the adjustment bolt on the side, top or bottom of the pulley counterclockwise with the ratchet and socket before item belt is loose enough to eliminate. 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 manuals 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 loss 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 degrade, causing noise and warmth. Pulleys are usually made of either plastic or steel, so examine the pulley itself for just about any damage aswell. At O’Reilly Automotive Parts, we’ve tensioner pulleys available for many vehicle models.
The programmed pulley tensioner has an internal spring-loaded mechanism that keeps the serpentine belt under frequent tension. Its design permits 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 moderate shock loads that happen when the air conditioning unit cuts on and off. As a regularly rotating component, the pulley tensioner can give off some warning signs 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 automated tensioner device or rot the shaft bearings, that will cause a frozen placement in the adjustment pressure. Without the correct pressure, the belt can slide.
Debris Contamination
Rocks, gravel and other highway debris could be thrown up in to the tensioner pulley grooves and jam the mechanism. This can permit the serpentine belt to slip on the tensioner pulley and burn. Overheated pulley temperatures results, and finally 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 contact with heat. This causes the belt to flutter and skip instead of maintaining a constant strain on the pulley. Symptoms of a fragile spring display as glazing on the underside of the serpentine belt, with an intermittent flickering of the dashboard’s charging light indicator. Squealing or squeaking will become listened to 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. Poor bearings trigger an audible growling noises. The external ends of the serpentine belt will fray and stretch the belt. Finally the rubber belt grooves flatten out and trigger major slippage. An excessively wobbling pulley can throw the belt off, causing all the components to quit functioning.
Lever Arm Freeplay
Some tensioner pulleys possess markings on the housing that indicate the maximum range 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 which has jammed in one 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 face 
of the tensioner pulley, and then flushing it against another item pulley, can gauge the angle. Any off-angle measurement indicates donned shaft bearings in the pulley casing.
Serpentine Belt Noise
A moderately donned serpentine belt gives off a constant squeaking noises during engine idle. Belts that contain worn severely project a loud chirping or squealing sound. The cause tips to a glazed, donned or cracked belt. Dry or partially frozen tensioner pulley bearings could cause such sounds by deteriorating the belt prematurely.
Lever Arm Oscillation
A lever arm that repeatedly oscillates back and forth 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 noises.