33 21... Ribbed teeth

WARNING: This page is about a different car, the 2009 BMW 550i and 2008 BMW 550i. However, it is still accessible from the selected car via links, so may be relevant.

IMPORTANT: Bolts with ribbed teeth must be replaced after they have been released!

Fig 1: Identifying Bolts With Ribbed Teeth

Courtesy of BMW OF NORTH AMERICA, INC.