This part is listed by BMW as BMW part number 12317550468 (12 31 7 550 468) and is described as OEM Overrunning Alternator Pulley for BMW E82, E9X, E84, N55.
This pulley is known as a overdriving, decoupling, OAD, or ADP pulley and has an internal dampening system that can wear out or fail. This can cause improper belt tension, vibration, slipping, noise, and poor alternator performance. There is no suggested replacement interval so check the overall condition of the pulley and listen for buzzing or squealing noises from the pulley itself. Removal and installation requires a special tool - see Related Items below.
This is an OEM Overrunning Alternator Pulley manufactured by INA Schaeffler - the original supplier to BMW for this part, as well as many other engine components. As the OEM it meets all of BMW's original design, fitment, and performance requirements and is TUV approved. OEM parts are the best alternative to more expensive Original BMW parts because they are virtually identical without the inflated price tag. This part has a two year warranty.
For full BMW fitment information or for assistance from one of our BMW experts, we recommend calling us at 877-639-9648.
BMW Fitments:
1 Series
E82 / E88 (08-13) > 135i N55 (11-13)
E82 / E88 (08-13) > 135is N55 (11-13)
3 Series
E90 / E91 / E92 / E93 (06-13) > 335i N55 (11-13)
E90 / E91 / E92 / E93 (06-13) > 335xi N55 (11-13)
X1 Series
E84 X1 (2013-2015) > X1 35i xDrive