Hi all: I agree with John about FR-12. I have used it in my 300F since 1996 and my vent temperature is about the same as John's, 38 degrees. Also, it is a lot cheaper than R-12 which the last time I looked was about $30/lb. vs. $8/lb for FR-12. FR-12 is fully compatible with R-12 but it is illegal to mix the two. The following URL provides an excellent discussion of FR-12. <A HREF="http://www.lenzdist.com/FrigcFAQ.html">Freon and freon alternatives from Lenz</A> Dan Reitz Northridge, CA [Non-text portions of this message have been removed]