The crankshaft pulley at the front end of the crankshaft drives alternators and other engine components. Crankshaft pulley, also known as harmonic balancer, is a visible wheel mounted on the crankshaft.

The crankshaft pulley is responsible for turning the belt for running the engine and other accessories. It has serpentine belts or separate belts for air conditioners and alternators. Unfortunately, over time, the pulley may break down and may need to be replaced.

Symptoms of crankshaft pulley failure include engine accessories not working or loud knock. Before replacing the pulley, it may be helpful to inspect the rubber insert between the center and the outside of the pulley. This rubber insert may be worn or damaged and cause timing problems or other symptoms. Sometimes the crankshaft bolt, which is responsible for fixing the pulley to the engine, may loosen; repair only requires tightening the bolt.

The driver should check the crankshaft pulley and its belt regularly for signs of wear or damage. Although it is not recommended for novices to undertake the task of replacing pulleys, it is usually a simple task for experienced mechanics.