1998 Cadillac Eldorado Owner's Manual - Page 263
1998 Cadillac Eldorado Manual
Page 263 highlights
a 4. With the coolant surge tank pressure cap off. start the engine and let it run until you can feel the upper radiator hose getting hot. Watch out for the engine cooling fans. By this time, the coolant level inside the coolant surge tank may be lower. If the level is lower, add more of the proper mixture to the coolant surge tank until the level reaches about 2.5 inches (6.4 cm) below the base of the filler neck. 5. Then replace the pressure cap. Be sure the arrows on the pressure cap line up like this. Start the engine and allow it to warm up. If the CHECK COOLANT LEVEL message does not appear on the Driver InformationCenter, coolant is at the proper fill level. If a CHECK COOLANT LEVEL message does appear, repeat Steps 1 through 3 or see your dealer. 5-23