Decoding Engine Squeals: A Guide to Accessory Belt Glazing and Tension | MyMechanic
What is a Glazed Belt?
Your car's accessory belt (or serpentine belt) is made of a durable, flexible rubber compound. When new, the side with the ribs has a pliable, matte texture that provides excellent grip on the engine's pulleys.
How to Assess Your Belt's Condition
The Visual Check:
1. Look for Shininess: A healthy belt has a dull, black, rubbery appearance. A glazed belt will look shiny and smooth on the ribbed side.
2. Check for Cracks: Look closely at the ribbed side of the belt. While a few tiny cracks may be acceptable on an older belt, if you see multiple cracks per inch or deep cracks that go down to the belt's fabric core, the belt is due for replacement.
3. Check for Contamination: Look for any signs of oil or coolant on the belt. These fluids will quickly degrade the rubber and cause slipping and squealing.
The Importance of Proper Tension
A belt can be in perfect condition, but if it isn't held tightly against the pulleys, it will slip. This is where belt tension comes in.
Automatic Tensioners: Most modern cars are equipped with an automatic belt tensioner. This is a spring-loaded or hydraulic arm with a pulley on the end that constantly pushes on the belt to maintain the correct tension. These tensioners can wear out, and a weak spring is a common cause of belt squeal.
Manual Tensioners: On older cars, the tension was often set manually by adjusting the position of the alternator or another accessory. These can loosen over time and may need to be re-tensioned.
Frequently Asked Questions
Conclusion
A squealing belt is your car’s way of telling you it needs attention. By learning to spot the signs of a glazed, cracked, or contaminated belt, you can address the problem before it leaves you stranded. For Singaporean drivers in Malaysia, this simple inspection is a great piece of preventative maintenance. When the noise starts, trust a professional service like MyMechanic to identify the true cause—be it the belt, the tensioner, or both—and recommend the correct fix.
Need Roadside Assistance?
A squealing belt is a sign that your car needs attention. For Singaporean drivers in Malaysia, MyMechanic offers on-site inspections to diagnose belt and tensioner issues. We can determine if you need a simple adjustment or a new belt and tensioner, solving the problem correctly.
