This part is listed by BMW as BMW part number 11367830829 (11 36 7 830 829) and is described as Genuine BMW O-Ring - 11367830829 - E39 M5.
This O-ring is the smaller of the 2 sizes used on the Vanos Solenoid Valve on the S62 Engine, which is found in the E39 M5 and E52 Z8.
Each Vanos Solenoid uses 4 of this O-ring, and there are 2 Vanos Solenoids per engine. Please order a total of 8 O-rings if you wish to replace them all.
For full BMW fitment information or for assistance from one of our BMW experts, we recommend calling us at 877-639-9648.
BMW Fitments:
5 Series
E39 (97-03) > M5 (00-03)
Z Series
E52 Z8 (00-03) > Z8 Roadster (2000-2003)