Benefits of a Billet Crank Seal Guard for BMW Owners Out of all the aftermarket options, it is possible to single out one that is an essential add-on part as the Billet Crank Seal Guard, which is offered to BMW buyers due to a critical weak point in a variety of BMW engines. It is a special part that provides vital backup against a failure mode that some owners of the BMW family might not even have known occurred. Click here for more info: https://paradigmengineering.co/blogs/news/benefits-of-a-billet-crank-seal-guard-for-bmw-owners