I know what you mean about the wind chill, but id guess the Rad would be a prime candidate for that too
![Wink :wink:](https://www.mk5golfgti.co.uk/forum/Smileys/newsmileys/wink.gif)
I had a look and most major brands of anti freeze only go down to -35 on a 50-50mix which is the strongest they recommend.
personally i buy what ever i see when i know i'm low, never had an issue yet
![happy2 :happy2:](https://www.mk5golfgti.co.uk/forum/Smileys/newsmileys/happy2.gif)