1998 Chevrolet Lumina Owner's Manual - Page 261

NOTICE: When adding coolant, is important thatyou use it only DEX-COOL@(silicate-free) coolant. If coolant other than DEX-COOL added to is the system, premature engine, heater core or radiator corrosionmay result. I n addition, the engine coolantwill require change sooner at 30,000 miles (50 000 km) or24 months, whichever occursfirst. Damage causedby the use of coolant other than DEX-COOL@ is not covered by your new vehicle warranty. What to Use Use a mixture one-half clean water (preferably of distilled) and one-halfDEX-COOL@ coolant which won't damage aluminumparts. If you use this mixture, you don't needto add anythingelse. -- Adding only plain water to your cooling system can be dangerous. Plain water, or some other liquid likealcohol, can boil before the proper coolant mixture will. Your vehicle'scoolant coolant warning systemis set for the proper mixture. With plain water the wrong mixture, or your engine could too hot but you wouldn't get get the overheat warning. Your engine could catch fire and or otherscould be burned. you Use a 50/50 mixture of clean water and DEX-COOL@coolant. 6-23