More and more engines are fitted with vibration damper (rubber-metal) at the  crankshaft to reduce oscillations. If vibration damper are not changed continuously, damage by vibration (even at auxiliaries) and increased noise development are implicated. This could raise serious consequences such as engine blow-up or failure. 

Take care of:

• damaged pulley
• fissures in Elastomer

Please keep in mind to check the driving pulley with each pulley change to prevent damage!