My radio "freezes" on occasion. What ever setting was left when car (96 xj6 - 130k miles) was turned of, is the setting. Can't shut off change station, change volume etc. After driving awhile, from a few minutes to up to an hour, it will work properly. I have the radio out of the car (thanks to the need for a new a/c evaporator). Any thoughts? Could escaping freon do this?