October 27th, 2014
Belt noise can be a real nuisance for your customers. Solving this problem for them can be simple, but there are many misconceptions on the proper way to address belt noise.
The most popular misconception is that you can simply treat belts with a chemical or solvent such as belt dressing, soap, brake fluid, silicone spray, or brake cleaner. These solutions are merely quick-fixes, and before you know it your customer will be back with the same belt noise issues. Even replacing the belt is a temporary solution, because belt noise is a signal that there is a problem somewhere else in the accessory belt drive system.
Our research indicates there are two main causes of belt noise.
The first is loss of tension in the pulleys. This is typically indicated by a squealing belt at engine startup. The belt squeals because tension has been lost momentarily between the belt and the pulley, usually because of a worn automatic tensioner, but other causes can include a contaminated belt (oil, belt dressing, etc.) or a belt that is too long or worn out. Loss of tension generates heat which can lead to premature failure of belts, pulleys, and component bearings.
The solution: The tensioner should always be the first component inspected when there is belt noise. If the tensioner is worn, it should be replaced. You should also inspect the accessory belt drive system for fluid contamination. If a leak is found, repair it and then inspect the system again to confirm the issue has been addressed.
The second main cause of belt noise is misalignment. A chirping belt typically indicates an alignment problem between component pulleys and idlers. Pulleys or idlers that are out of alignment by as little as one degree can create belt chirp as the belt ribs slide down one side of the pulley grooves.
The solution: If you hear belt chirp, address the alignment issues.
By solving the root cause of belt noise, you can address belt noise issues the first time and avoid customer comebacks. For more information about heavy-duty belt noise and how to address it, watch this short video.