How to Check Belts

Co-authored by Duston Maynes

Last Updated: January 22, 2023 References

The belts in your car's engine drive such components as the air conditioning compressor, power steering pump, alternator and water pump. Older cars used separate V-belts for each component, while newer cars use a single serpentine belt to drive them all. Belts wear and tear over time, and a belt's failure could mean serious damage to the engine or its systems. You need to check your belts on a regular basis; here's what to look for.

Steps

1
Listen for squealing sounds from the engine when you drive. These sounds likely mean one or more belts are worn, loose or damaged.
2
Check belts for signs of wear. You need to do more than just visually inspect the belts. Pinch, squeeze and twist them, looking for cracks, fraying, splits or brittle places.^{[1]
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- On a serpentine belt, also look for missing grooves or places where the belt's layers have separated.^{[2]
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3
Check your belts for places where the rubber is slick or glazed in appearance. Slick spots can cause a belt to slip and may be precursors to overheating and cracking.
4
Inspect the pulleys. Look for a buildup of rubber deposits, as well as worn spots that could catch the belt and cause it to break.^{[3]
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- Also check the belts' alignment on the pulleys. They should line up straight on the pulleys.
5
Check the belt tension. Check the tension on the longest length of the belt; there should be no more than one-half to one inch (1.25 centimeters to 2.5 centimeters) of give.^{[4]
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Community Q&A

Question

I have a dead rat in my car and it stinks. What can I do to get the smell out?

Community Answer

Get the rat out. Then wash your engine with petrol or a chemical called prepsol -- it's a cleaning product.
Question

How can I check the tension on a belt?

Community Answer

Twist it if you do not have a tensioner test. The longer you can twist it, the belt is loose, the less it twists, the belt is good. You must have a good vision of comparing.

Warnings

If the V-belt for your water pump breaks, your engine temperature will rise rapidly. If the V-belt for your alternator breaks, your alternator no longer will supply power to your battery to keep it charged, and the compressor for your air conditioner will also quit. If your car has a serpentine belt and it breaks, all these things will happen. If your car starts to overheat, pull over immediately.

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Many of the new composite belts will not show signs of wear until they break.

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