Skip to main content

What should I do if the belt is making a squealing noise?

May 13, 2021

A squeal is usually caused by low bely tension or contamination. To rectify the problem, we suggest the following steps:

  • Properly tension manual applications during installation (35 lbs. per rib) and then re-tension after 5 minutes of run-in (30 lbs. per rib). This allows the belt to seat in the pulleys.

On vehicles with automatic belt tensioners, the tensioner pulley should turn freely without binding. The tensioner arm should move smoothly through its entire range of motion and there should be adequate tension. Always check the tensioner bearing for noise and wear. Replace any tensioner where the bearing feels rough or the pulley has signs of excessive run-out (wobble).

  • With the belt removed, inspect all accessory pulleys and idlers to ensure free and smooth rotation. If there is binding or rough rotation (dry bearing), then the pulley and/or accessory should be replaced.
  • Check for contamination. If the belt has been in contact with motor oil, power steering fluid, antifreeze or any other petroleum-based lubricant, it will cause the EPDM belt to swell, leading to noise. Other than washer fluid, replace any serpentine belt that has been oil soaked. NEVER try to solve issues with belt dressing.