What exactly does a harmonic balancer (sometimes called a dampener) do? Each time a cylinder fires in your engine, a force acts upon the crankshaft, causing it to twist. This force also causes vibrations in the crankshaft. These vibrations from the engine can become too much for the crankshaft to bear, causing it to fail.
This is where the harmonic balancer comes in. The circular device, made of rubber and metal, is bolted at the front end of the crankshaft to help absorb vibrations. ItÕs usually connected to the crank pulley, which drives accessories like the air conditioner. The rubber inside the pulley is what actually absorbs the vibrations and keeps them at a safe level.