Our plant is in Northern BC, Canada. During the winter our temps get down to -45 C. We use a 60/40 mix in the LT system and a 80/20 mix in the HT system. Our engines were de-rated because of the use of glycol. After 6 years of operation we have never had a freeze up. The cooling system has an electric pre-heater and circulation pumps for when the engines are shutdown