I don't think you can insulate your bow against the heat in a vehicle if setting out all day. The temp in a vehicle setting in the sun on a hot day can get to 150 or more. I do not leave my bow or gun in the truck under these conditions, not worth the risk. To answer your question I don't think old or new will take it. Even if the limbs will take it I think the cables and string will stretch in the heat.
IMO
David/Mo