Rick's Free Auto Repair Advice

Discover What Belt Dressing Does (and Does Not Do)

Belt dressing does stop belt noise temporarily, but no, it doesn’t fix the problem

Belt noise; squeal, chirp or whine are caused by one of four things and belt dressing can’t fix any of them. Spraying it on your belts may give you a temporary reprieve from the noise, but it doesn’t fix the root problem of:

• Improper belt tension (too loose)
• Worn out or glazed belt due to slipping
• A binding/sticking idler or rotating component
• A component that’s out of alignment.

What’s in it?

Belt dressing, also mistakenly called “belt conditioner” is really just a sticky spray to increase grab between the belt and the pulleys. The spray has some temporary lubricating properties but they don’t last long and the belt noise always returns. Here’s what’s in belt dressing:

• Hydrocarbon Polymer — A tacky substance similar to an adhesive that adds stickiness and helps seal the belt surface to reduce friction noise.
• Non-Chlorinated Hydrocarbon Solvent — The solvent serves two purposes: 1) it’s the carrier for the tacky adhesive, and 2) it cleans the belt and pulley.
• A Petroleum-Based Oil or Synthetic Polymer — This is the “conditioning” part of the formula. It reduces friction between the belt and pulleys to reduce noise. Unfortunately, reducing friction is not a good thing when you’re using the belt to rotate important components. It’s why belt dressing works for a while and then the belt starts slipping and making noise again. In addition, the oil and polymers are supposed to  keep the rubber supple, prevent drying, and minimize slipping. However, if the belt is dry, it should be replaced. If it’s making noise, you need to fix the underlying cause.

Is there a downside to using belt dressing?

YES! Belt dressing is mainly a tacky adhesive, it tends to pick up and retain dirt and grit which it them grinds into your belt and pulleys, wearing them both out prematurely. It’s really no different than spraying your bicycle tires with adhesive and then being amazed that they pick up all the sand and dirt you drive though.

Don’t use belt dressing. Find the real cause of belt squeal and chirp

So what’s the real fix? Belts squeal and chirp because:

1) the belt is worn or glazed
2) the belt is too loose or too tight. If you have an automatic tensioner, the only fix is to replace the tensioner.
3) an idler pulley is presenting resistance and not turning as fast as the belt
4) One of the drive units is out of alignment

Locate the belt noise

serpentive belt tensioner, belt dressing, belt squeals, belt chirps

Automatic Belt Tensioner

How to diagnose belt noise.

© 2012 Rick Muscoplat

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Posted on by Rick Muscoplat



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