The Vanos oil restrictor O rings should be changed at regular intervals on the S54 engine (E46 M3, late Z3M and Z4M). This kit includes the two associated O rings but in Viton, a material of far greater quality and rating than BMW’s cheap O rings. Results in greater oil pressure regulation and service life.

Includes uprated Viton O rings, as direct replacements for BMW part numbers:

11311318659 – small O ring
11361403325 – large O ring