[TheSlavik]

I know C02 is fine inside the cooler, but am unsure about beergas. If you had you gas in the cooler for all your other kegs and had no problems, I would say it should be fine. By the sounds of things your doing it all right. You didnt partially freeze the keg did you? I froze my Guinness keg and it was game over after that. Your temps are a bitlower than what Guinness reccomends, they call it at 42 degrees.