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A tensioner maintains the correct amount of tension on the belt at all times throughout its duty cycle. It also helps protect other components such as the alternator and water pump from undue stress and premature failure. In addition, a tensioner is a relatively inexpensive part to replace.
How does an auto belt tensioner work?
The automatic belt tensioner is a spring-loaded idler pulley that maintains constant tension on the drive belt at all engine speeds. The faster that the engine turns, the belt gets stretched more which actually makes the belt loose.
How does a tensioner work?
A tensioner is a device that applies a force to create or maintain tension. The force may be applied parallel to, as in the case of a hydraulic bolt tensioner, or perpendicular to, as in the case of a spring-loaded bicycle chain tensioner, the tension it creates.
How does a belt tensioner fail?
Over time, this will increase belt wear and lead to premature belt failure. A worn bushing in the tensioner pulley, can cause vibrations and noise. If the bushing seizes, it may cause the belt to snap. A weak or broken spring inside the tensioner, can’t maintain proper tension and the belt will slip.
Does a belt tensioner spin?
Checking the Tensioner Spin the pulley to see if it spins freely. If you hear grinding or the pulley doesn’t spin freely, replace the tensioner. When you replace the belt, it should take a lot of muscle power to move the tensioner. If you can move it easily, the spring tension is most likely not tight enough.
Are all belt tensioners the same?
There are three main types of belt tensioners found in the replacement auto parts market. Each one works a little differently, but all ensure that your alternator and auxiliary pumps receive the power needed to keep your car or truck moving.
How do I know if my tensioner is bad?
Grinding or squeaking noise from the belts or tensioner The most common symptom of a bad or failing drive belt tensioner is noise from the belts or tensioner. If the tensioner is loose the belts may squeak or squeal, especially when the engine is first started.
What does a bad belt tensioner sound like?
Grinding or squeaking noise from the belts or tensioner If the tensioner is loose the belts may squeak or squeal, especially when the engine is first started. It is also possible for the tensioner pulley or bearing to wear out, in which case the vehicle will produce a grinding noise from the pulley.
Can you tighten a tensioner?
Turn the adjustment bolt on the side, top or bottom of the pulley counterclockwise with the ratchet and socket until the accessory belt is loose enough to remove. Tighten the tensioner pulley by turning the adjustment bolt clockwise with the ratchet and socket until the belt is tight.
Can a tensioner pulley leak oil?
The hydraulic oil that maintains this tension can seep out of the tensioner. When it does the associated engine belts become loose. A car that leaks oil is not an uncommon sight. This is often due to a loose timing belt, which arises due to leaking from the tensioner.
Why is my belt tensioner shaking?
Causes of Belt Tensioner Wobbling In general, belt tensioners tend to get noisy when they fail. If your belt tensioner is chirping or makes other noises, it is often an indication that the part is old and needs to be replaced. You can even remove the belt, spin each pulley, and listen for rumbling or other noises.
Should you replace tensioner with serpentine belt?
There is no recommended timeframe in which to replace your tensioner, especially as the belt itself usually needs replacing before the tensioner does. However, you should inspect your tensioner each time you service your car to monitor its condition and replace it if necessary.
Can a belt tensioner leak?
Problems with hydraulic belt tensioner. It too can fail. Symptoms include a leak from the tensioner or a rattling noise from the belt area when the engine is running. This item is common to fail in many cars including Toyota Corolla, Matrix, BMW and Mazda cars. The fix is the same; a bad tensioner must be replaced.
Should a tensioner move?
Appearance: Cycle the tensioner (mounted on the engine) through the entire range of motion (from stop to stop) by applying torque to the arm with a wrench. The tensioner arm should move smoothly and freely. Solution: If you notice a binding, sticking or grinding tensioner arm, the tensioner should be replaced.
Can a bad tensioner cause engine vibration?
Grinding noises – Grinding and rumbling noises are another common sign of tensioner or idler pulley failure, usually due to failing bearings. Excessive tensioner movement – Worn-out coil springs can also cause drive belt tensioners to loosen their grip on the drive belt, resulting in excessive vibration and rattling.
Can a bad belt tensioner cause misfire?
The belt may oscillate between too little tension and too much tension. The belt will slip and catch, causing noise and vibration. This can cause a change in crankshaft speed that can be severe enough to cause the engine management system to think that a misfire just occurred.
What happens if tensioner pulley breaks?
When the tensioner or tensioner pulley fails, the loss of tension can cause the belt and pulleys to make high-pitched rattling or chirping noises. If the pulley bearing completely fails, it can also cause a squealing or even a grinding noise. Symptom 2: Knocking or slapping. This can cause a slapping or knocking noise.
Why do V belts fail?
Missing cogs can cause belts to slip and fail, when it is discovered there are teeth missing, the belt should be changed immediately. The most common reasons your belt could be missing a cog are excessive heat, the pulleys are too small or misaligned. It can also be caused by improper or prolonged storage of belts.
How long do belt tensioners last?
Most modern cars that roll off the dealer’s lot as a new vehicle will have a 60,000 to 100,000-mile life expectancy for the serpentine belt, tensioners, and idler pulleys.
