1993 Cadillac Eldorado Owner's Manual - Page 295

Specification 1825-M with a complete coolant flush and refill. Use GM Engine Coolant Supplement (sealer) with any complete coolant change. If you use these,you don't need to add anything else. I Adding only plain water to your cooling system can be dangerous. Plain water, or some other liquid like alcohol, can boil before the proper coolant mix will. Your vehicle's cwlant 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 getthe overheat warning. Your engine could catch fire and you or others could be burned. Use a 50/50 mix of dean water and a proper anti€reeze, 281