Genuine BMW Idler Pulley - Multiple BMWs

This is a Genuine BMW Upper Idler Pulley, also known as the roller pulley or deflection pulley. The upper and lower idler pulleys are known to be the primary sources for 'belt squealing'. The pulley is also encased in rubber which will crack over time. If left without service the rubber could fail completely, chucking the belt and leaving you stranded. Replacement is a very simple procedure and can be done anytime the fan is off the engine (belt replacement, water pump service, alternator replacement, etc).