1998 Cadillac Eldorado Owner's Manual - Page 304

Checking Coolant A CAUTION: Turning the surge tank pressure cap when the engine and radiator are hot can allow steam and you scalding liquids to blow out and burn badly. Never turn the surge tank pressure cap even a little when the engine and radiator arehot. -- -- . The surge tank is located next to the engineblock on the passenger's side of the engine. The cooling system is under a lot of pressure when it is hot. If the CHECK COOLANT LEVEL message appears on the Driver Information Center (DIC), you will need to add coolant. When your engine is cold. the coolant level should be at the full cold mark, which is 2.5 inches (6.4 cm) below the base of the fill neck. Use a flashlight as necessary to see into the tank. ... If the CHECK COOLANT LEVEL message comes on. it means you're low on engine coolant. For more information, see "Check Coolant Level" message in the Index. 6-24