1998 Buick Regal Owner's Manual - Page 288

NOTICE: When adding coolant, it important thatyou use is only DEX-COOL@(silicate-free) coolant. If coolant other than DEX-COOL is added to the system, premature engine, heater core or In radiator corrosion may result. addition, the engine coolantwill require change sooner at 30,000 miles (50 000 km) or24 months, whichever occurs first. Damage caused the use by of coolant other than DEX-COOL@ is not covered by your new vehicle warranty. What to Use Use a mixture of one-half clean water (preferably distilled) and one-half DEX-COOL@coolant which won't damage aluminum parts. If you use this mixture, you don't need to add anything E :. -- Adding only plain water to your cooling system can be dangerous. Plain water, or some other liquid like alcohol, can boil before the proper coolant mixturewill. Your vehicle's coolant warning system is set for the proper coolant mixture. With plain water or the wrong mixture, your engine could get too hot you wouldn't but get the overheat warning. Your engine could catch fire and or others could be burned. you Use a 50/50 mixture of clean water and DEX-COOL@coolant. 6-24