Take a look at Castrol 5w-40 it states on the label that it is designed for bmws. It also meets all certifications for Castrol 0W-30. If you go by certification you would think that Castrol 5w-40 is the same as Castro's 0w-30. However, Castrol's website shows that their 5w-40 is NOT for bmws that require LL01 ( see link, page 2) [
http://www.castrol.com/liveassets/bp...syntec_usa.pdf This LL01 cert must mean something. Why risk using royal purple or amsoil or any other oil without that LL-01 certification? Castorl 0W-30 and Mobil 1 0-40 have that certification. The complete list can be found on BMW's website
http://www.bmwusa.com/Standard/Conte...ngineOils.aspx