After nearly a year of putting up with frequent, intermittent and increasingly annoying dash rattles and after listening, pushing and prodding all over the dash, I went to the dealer and asked what they thought. Although they immediately heard the noise, they "couldn't put their finger on it." My SA did offer to take the dash apart in an effort to resolve my problem.
However, that violates my cardinal rule with dealers that 'less is always more", so I declined.
Then after a particularly noisy and annoying drive I got motivated and decided to fix it myself, no matter what. What I found was that if I pushed at the bottom of the clear plastic instrument window where it meets the flat part (where the dust collects), the noise stops.
So after thinking about something I could slide in there. I decided to try a black guitar pick and viola...NO MORE RATTLES
It's not a BMW factory part and my detail guy was very curious about it, but it does work. Sweet silence.
