Crankshaft lifespan is influenced by various factors and there is no fixed standard. Generally speaking, a car engine crankshaft can last 10 to 15 years without problems, and with proper maintenance, it can even last 20 years. For example, a Weichai original forged steel crankshaft can normally last over 600,000 kilometers, while a spare ductile iron crankshaft lasts around 300,000 kilometers. A three-wheeled vehicle crankshaft, as long as the engine oil is kept at a normal level and the engine doesn't overheat, can last over 30,000 kilometers; if the engine oil is in good condition within its normal lifespan, it generally doesn't need to be changed. However, if maintenance is not timely, or if driving habits are aggressive, the crankshaft may wear out severely after only a few thousand or 10,000 kilometers.
Furthermore, crankshaft lifespan is also affected by road conditions, crankshaft quality, engine operating conditions, and other factors. For example, poor road conditions, severe overloading, frequent operation of the engine within the torsional vibration critical speed range, and shock absorber failure can all cause crankshaft torsion vibration fatigue failure and breakage.
