Originally Posted by BMWN54tech
Lifter tick. Although its more common on the N52, it does happen on N54 engines. Removing the camshafts and replacing the lifters is the fix. If you were more local I could help you out better.
Would this be covered under CPO warranty? I will go talk to the dealer. I had a similar sound before, and it turned out to be a loose TQ converter bolt. It was not torque down right. I wonder if it is the same thing, but I will mention the lifter issue to them.