1998 Buick Regal Owner's Manual - Page 248

How to Add Coolant to the Radiator I NOTICE: Your engine has a specific radiator fill procedure. Failure to follow this procedure could cause your engine to overheat and be severely damaged. 2. Then keep turning the pressure cap, but now push down as you turn it. Remove the pressure cap. . . You can remove the radiator pressure cap when the cooling system, including the radiator pressure cap and upper radiator hose, is no longer hot. T r the un pressure cap slowly counterclockwise until it first stops. (Don't press down while turning the pressure cap.) You can beburned if you spill coolant on hot engine parts. Coolant contains ethylene glycol and it will burn if the engineparts arehot enough. Don't spill coolant on a hot engine. If you hear a hiss, wait for that to stop. A hiss means there is still some pressure left. 5-22