1998 Cadillac Eldorado Owner's Manual - Page 260

How to Add Coolant to the Coolant Surge Tank If you haven't found a problem yet, but the coolant level isn't at the proper level (2.5 inches (6.4 cm) below the base of the fill neck), add a 50/50mixture of clean water (preferably distilled) and DEX-COOL@coolant at the coolant surge tank, but be sure thecooling system, including thecoolant surge tank pressure cap, is cool before you do it. (See "Engine Coolant'' in the Index for more information.) I A CAUTION: Steam and scalding liquids from a hot cooling system can blow out and burnyou badly. They are under pressure, and if you turn the coolant surge tankpressure cap even a little they can comeout at high speed. Neverturn the cap when the cooling system, including the coolant surge tank pressure cap, is hot. Wait for thecooling systemand coolant surge tank pressure cap to coolif you ever have to turn the pressure cap. -0 -- Adding onlyplain water to your cooling system can be dangerous. Plain water, or some other liquid like alcohol,can boil beforethe proper coolant mixture will. Your vehicle'scoolant warning system is set for the proper coolant mixture. With plain water or the wrong mixture, your engine could get too hot you wouldn't but CAUTION: (Continued) 5-20