What Causes Belt Noise?


A common misnomer is thinking the drive belt is the cause of belt noise, when in fact it usually is caused by an external source. The leading causes of drive belt noise are either:

  • Pulley misalignment
  • Insufficient belt tension

It is important belt noise is diagnosed and rectified, if not a number of issues could arise, including:

  • Insufficient charging from the alternator
  • Possible overheating from inferior cooling system performance
  • Belt noise can reoccur
  • May cause the check engine light to illuminate
  • Could result in a misdiagnosis of the check engine light

Watch Gates video on how to diagnose belt noise using the spray bottle test:

Be System Smart - INSPECT - 100, REPLACE - 150

System failures can lead to expensive engine repairs. The best way to prevent this is to remember to start inspecting the serpentine systems at 100,000 km and replace worn components by 150,000 km or as advised by the manufacturer.

It is vital to inspect all drive system components, including:

1. Idler Pulleys
Smoothly connects the belt to the system. Worn pulleys can misalign and cause system damage.

2. Alternator Decoupler Pulley
Transfers power from the belt to the alternator, keeping the battery charged. Wear is a common cause of charging problems.

3. Serpentine Belt
Powers many key components like the alternator and air conditioner compressor. Just 5% wear can negatively affect performance.

4. Belt Tensioner
Maintains consistent tension on the belt. A loss of tension can create noise and heat, leading to premature belt failure.

5. Torsional Vibration Dampers
Crankshaft pulley with a rubber damping element to absorb vibrations from the crankshaft and extend the lifespan of the crankshaft, the multi-ribbed belt and all belt-driven components.

The Gates brand of serpentine system replacement parts is trusted by vehicle manufacturers, recommended by quality mechanics and relied on by motorists. Be sure to use Gates parts when it’s time for replacement.

Gates belt wear gauge in use

This small, lightweight tool provides a simple and reliable way to determine belt wear by gauging material loss between belt grooves and providing instant pass/fail results.

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