A Harmonic Balancer, also known as a dampener, aids in keeping the crankshaft working as long as possible, preventing engine failure. This is because the cylinders in the engine generate torque when they fire, which is subsequently passed along to the crankshaft. This crankshaft twists every time a cylinder fires, which also causes vibrations in the crankshaft which can resonate. These vibrations can overstress the crankshaft and cause it to fail.
More Information on Harmonic Balancers
The harmonic balancer is connected to the crank pulley, which also helps to control accessories like the A/C. It has a rubber section which helps with absorbing the vibrations, bringing them to a safer level. This rubber segment, like any other part, can begin to wear with use and soot build up. There is even a special tool, the harmonic balance puller which is able to extract damaged or worn out dampeners without hurting any other parts in the vehicle.
