Is there any reason people don't use Autofrost instead of converting to 134? I've used it for many years with great results and it uses the same oil and will mix fine with R12. http://www.refrigerantsales.com/ http://www.cooltop.net/autofrost.html http://www.thirdgen.org/techboard/cooling/428019-r406a-autofrost-review.html Joel McGregor