In my old 240 ('83 242 GLT) I had a sunroof problem. I owned the car for about 3.5 years and never had a problem, I loved the sunroof. But by this point she was getting tired and I was close to replacing her. She must not have been happy with me having these thoughts because one day I was cruising down the highway at about 70 mph with the sunroof closed. All of a sudden the roof opened on its own just a crack, apparently from the wind. In an instant the roof was gone! Blown right off the top of my car. I just saw it rolling around the shoulder in the rearview. Luckily no one was behind me or it could have been a real disaster. I was able to find a replacement at the wreckers and fixed it the same day and never had another issue with it for the remaining 6 months or so that I owned her. I now have a '92 245 and really miss the sunroof. Just check what the others have mentioned and if all looks good enjoy the sunroof and don't worry. I think my problem was a rarity.