* Vibration: Excessive vibration, especially at idle or low RPMs. This is the most common symptom. The vibration can be felt throughout the car.
* Rattling or knocking *sound* from the front of the engine: While not a deep knock, you might hear a rattling or knocking sound emanating from the area of the harmonic balancer. This is due to the separation of the rubber or the internal components.
* Erratic idle: The engine might idle roughly or inconsistently.
* Misfires or hesitation: A severely damaged balancer can affect timing enough to cause misfires or hesitation during acceleration.
* Belt squeal or slippage: If the balancer is wobbly, it can misalign the crankshaft pulley and cause belt problems.
* Check engine light: In some cases, a failing balancer might trigger a check engine light due to misfires or other related issues.
The key difference is that the sound associated with a bad harmonic balancer is often more of a *vibration-induced* rattle or knocking sound, rather than the deep, metallic *knock* associated with internal engine damage.
If you suspect a bad harmonic balancer, it's best to have it inspected by a mechanic. Ignoring the problem could lead to more serious engine damage.
