If there is a small chunk of rubber missing on the grooved side of the belt, it will make a repetitive clicking noise over one of the pulleys.

It will sound more like a bad pulley than a worn belt.

Replacing the belt is a cheap and necessary repair anyway, and might eliminate the problem to boot.

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2009 ML350 (106K) - Family vehicle
2001 CLK430 Cabriolet (80K) - Wife's car
2005 BMW 645CI (138K) - My daily driver
2016 Mustang (32K) - Daughter's car