I had my F30 330d in the dealer today for the EGR cooler recall, and was pleased when it got a clean bill of health. This didn't last long as there was a persistent rattle on the way home that sounded like metallic trim resonating at various speeds - really annoying. So I immediately assumed that when they had stripped the car a couple of hours before, they had failed to re-install the trim properly. So a quick phone call and it was straight back to the dealership. The service guy suggested the most likely cause to be the engine cover not seated properly. Half an hour later and the car was back out of the workshop - all fixed. But it wasn't - as soon as I drove down the road, the noise was still there! So straight back into Service Reception. This time they sent a technician out with me for a road test. After driving a few miles, he finally located the resonating rattle to be coming from the rear headlining, just above the rear windscreen where the brake light strip is. The remarkable coincidence is that this only happened after it had been into the workshop today, I've never heard this noise before. So nothing they did in checking the EGR could have caused it. Anyway back into the workshop one last time and they found a loose trim clip in the headlining that holds the brake light strip in place. Strange how these things suddenly occur at the same time - it's easy to jump to the wrong conclusion. Finally it was all sorted, and the good thing is that they have put it through as a back dated warranty claim, so hasn't cost me a penny. Sometimes when you least expect it, a dealer surprises you with their excellent service. I'm now a happy man.