1998 Cadillac Seville Owner's Manual - Page 257

How to Add Coolant to theCoolant Surge Tank If you haven't found a problem yet, but the coolant level isn't at or above the mark at the forward edgeof the fill surge tank, add 50/50 mixture of clean water a (preferably distilled) and DEX-COOL@ coolant at the coolant surge tank, but be sure the cooling system, including the coolant surge tank pressure cap,cool is before you do it. (See "Engine Coolant" the Index for in more information.) Steam and scalding liquids from a hot cooling system can blow out and burn you badly. They are under pressure, and if you turn the coolant surge tank pressure cap even a little they turn the cap can come out at high speed. Never when the cooling system, including coolant the surge tank pressure cap, is hot. Waitfor the cooling system and coolant surge tank pressure cap to cool if you ever haveto turn the pressure cap. -- -- 5-20