WARNING: This page is about a different car, the 2013 BMW X5 M, 2012 BMW X5 M, 2011 BMW X5 M, and 2010 BMW X5 M. However, it is still accessible from the selected car via links, so may be relevant.
0491388 170004 Adapter MW
NOTE:
(Adapter) For screw-on radiator caps (standard thread)/ Series: E28, E30, E32 / Engine: M51 Free only for motorcycle!!! [Discontinued]