Engine Harmonic Balancer

Source: http://www.2carpros.com/how_does_it_work/harmonic_balancer.htm

A harmonic balancer is connected to the front of the engine crankshaft and is designed to help reduce vibration. The harmonic balancer is comprised of two separate pieces, the first is the mass which connects to the crankshaft and the second is the energy dissipating element. These elements are separated by a rubber insulator. The mass is designed to absorb vibration created from the crankshaft while in operation.

Harmonic Balancer

Failed Harmonic Balancer

Almost all vehicles are equipped with a harmonic balancer. Due to the stress and strain that is placed upon the harmonic balancer the unit can sometimes crack or separate. If upon inspection the harmonic balancer shows signs of weakness such as cracks, missing pieces or misplaced insulator you will need to replace the balancer. To replace the harmonic balancer a special tool is required. A balancer that is damaged can cause excessive strain on the engine

crankshaft. In extreme cases it can require the crankshaft to be replaced as well as the harmonic balancer. If the harmonic balancer is exposed to oil it can cause the balancer to fail. Check for oil leaks to prevent failure of the harmonic balancer. Proper engine performance

can keep the harmonic balancer operational. The balancer can be overworked by a poorly running engine.