Quote Originally Posted by rspears View Post
I agree with OSK. At the very least I'd paint a piece of sheet metal, let it cure and then put it inside a vehicle closed up in the sun. It's one thing to have no odor out in open space, but totally different when the interior gets up to ~150F with zero circulation.
Have you checked out BQuiet sound deadener? B-Quiet sound deadening material
I used BQuiet Ultimate in my coupe and highly recommend it. I also used a jute pad with aluminum backing under the carpet. It worked very effectively in reducing heat as well as sound. I would be careful about using anything that would produce any kind of fumes or expose you to something toxic. Sometimes cheap is not a good solution.