ACDelco Premix Coolant provides year-round frost and corrosion protection. Our premix coolant is already mixed at a ratio of 50% coolant and 50% water to ensure good corrosion protection and provides frost protection down to -37°C. Whilst the 50:50 mixture is typical, especially within Northern Europe, it can be diluted further and a ratio of 33% ACDelco Premix Coolant provides frost protection to -18°C. Mixtures with more than (approx) 70 vol. % of ACDelco Premix Coolant in water are not recommended.