Hey I recall a thread about someone having issues with the bolt coming loose on the engine damper on a 328. I noticed that there is a service bulletin on this dated 8-10-87, service bulletin #10-21. It states that from chassis number 68881 all engine damper bolts are tightened to spec with Loctite 242 thread locking compound. So sort of implies that those made before, should probably have this done. They state it is simply a "production change".