I just leased a Limited with the same problem. It was evident the first day I drove home. After numerous attempts to resolve the problem and a week at the dealer's service center, they discovered the problem was the bolts holding the rear (third sunroof). After tightening the bolts 3 times they found it was quiet when at normal temps. As stated, when the temp. went up, the rattle came back each time. I think they have finally resolved the problem. They installed nylon washers between the roof and the mountings. This stopped the problem. I had them run a second test drive after the car sat in the hot Florida sun for 5 hours. When I drove it home Friday, in the heat, no noise. I hope it is finally resolved. Go luck, the noise is nerve wracking. I was ready to return the car and/or file a lemon law claim. Joe