The engine pulley of a car should be replaced every 2 years or 60000 kilometers. The pulley and belt are together, so they should also be replaced together. The installation of car engine pulleys is a very complex project, and it is recommended not to install them on your own. Let professional 4S store personnel install them. Belt and pulley are important components of the engine valve system, which are connected to the crankshaft to ensure the accuracy of intake and exhaust timing with a certain transmission ratio. Pulleys belong to the category of hub components and generally have relatively large relative sizes. In terms of manufacturing processes, casting and forging are the main methods, and cast steel is rarely used. However, smaller sizes can be designed as forged and made of steel.