1998 Cadillac DeVille Owner's Manual - Page 311

Checking Coolant l'brning the surge tank pressure when the cap engine and radiator are hot can allow steam and scalding liquids to blow and burnyou badly. out Never turn the surge tank pressure cap even a little when the engine and radiator are hot. -- -- L When your engine cold, the coolant level should be is at theFULL COLD mark, whichis 2.5 inches (6.4 cm) of below the base the fill neck. Use a flashlight as necessary to see into the tank. ~MIUM UNLEADED ONLY FUEL II D J J J J D M K The surge tank is located next to the engine block on the passenger's side of the engine. The cooling system is under a of pressure when it is lot hot. If the CHECK COOLANT LEVEL message appears on the Driver Information Center (DIC), you will need to add coolant. HHrnrnrnrn 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.