1996 Cadillac Eldorado Owner's Manual - Page 242

~ Adding only plain water to your cooling system can be dangerous. Plain water, or some other liquid likealcohol, can boil before the proper coolant mix will. Your vehicle'scoolant warning system is set for the proper coolant mix. With plain water or the wrong mix, your engine could get too hot but you wouldn't get the overheat warning. Your engine could catch fire and or you others could be burned. Use a 50/50 mix of clean water andDEX-COOL antifreeze. TM 5-21