What does a bad harmonic balancer sounds like?

A bad harmonic balancer often produces a rattling or clunking noise, especially during engine idle or acceleration. You might also hear a rhythmic thumping sound as the engine runs, which can indicate that the balancer is failing to effectively dampen vibrations. Additionally, if the balancer is severely damaged, you may notice a scraping or grinding noise if the rubber isolator has deteriorated. These sounds can signal that the harmonic balancer needs to be inspected or replaced.