Sounds like loose metal when closed only. No rattle if in vent position or full open. Any suggestions? Thanks!

 

I suggest you turn up the radio when sun roof is closed lol

This is common problem on these cars, you either have to live with it or take apart sun roof assembly to fix it.

 

It has happened to both my girlfriends C70 and now mine, there's a metal bar glued to each of the long edges of the glass and the glue fails eventually and they fall off. I think they serve as weights or something, but I'm not sure. You can just take the bars out when they do fall off, sand off the old glue and re-glue it with glass epoxy or something. Good luck!

 

Thanks Cactuslegs! When my wife gives me back my baby, I will look @ that & do the fix!