How to Troubleshoot a Harmonic Balancerby Alibaster Smith
The harmonic balancer in your vehicle is a pulley that sits on the end of your crankshaft. It is typically on the driver's side of the engine. The pulley drives your timing belt in most cases, and absorbs the resonance created by your engine's combustion cycle. Over time, your balancer will fail. Troubleshoot the problem before you replace it to be sure the issue is with the balancer.
Loosen the lug nuts on the driver-side wheel by turning them 45 degrees counterclockwise with a tire wrench.
Raise the front of the vehicle onto jack stands. Lift up on the front cross member or front jack point and place jack stands under the front pinch welds. Then, lower the vehicle onto the stands.
Finish removing the lug nuts and pull the wheel off the wheel hub assembly.
Remove the inner wheel lining by prying off the plastic rivets that hold the lining in place using a flat-tip screwdriver.
Turn the engine on and examine the harmonic balancer. The balancer will be the only pulley visible in the wheel well. If the balancer wobbles at all, it needs to be replaced. This is the only reliable sign you will get that your balancer is about to fail. Some balancers may "hum" when they are about to fail, but your balancer will begin to wobble (as a result of becoming twisted or warped over time because of the resonance) when it needs to be changed.