2001 Cadillac DeVille Owner's Manual - Page 291

If there seems to be no leak, with the engine on, check to see if the electric engine cooling fans are running. If the engine is overheating, both fans should be running. If they aren't, your vehicle needs service. CAUTION: (Continued) surge tank pressure cap -- even a little -- they can come out at high speed. Never turn the cap when the cooling system, including the coolant surge tank pressure cap, is hot. Wait for the cooling system and coolant surge tank pressure cap to cool if you ever have to turn the pressure cap. 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 50/50 mixture of clean, drinkable water and DEX-COOLR coolant at the coolant surge tank, but be sure the cooling system, including the coolant surge tank pressure cap, is cool before you do it. See "Engine Coolant" in the Index for more information. CAUTION: 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 CAUTION: (Continued) 5-14