1997 Cadillac DeVille Owner's Manual - Page 264

I A CAUTION: Adding only plain water to your cooling system can be dangerous. Plain water, some other or liquid like alcohol, can before the proper boil coolant mix will. Your vehicle's coolant warning system is set for the proper coolant With mix. plain water or thewrong mix, your engine could get too hot but wouldn't get theoverheat you you warning. Your engine could catch fire and or others could be burned.Use a 50/50 mix of clean water and DEX-COOL@coolant. 'I, :.bH .