1997 Chevrolet Astro Owner's Manual - Page 282

I NOTICE: When adding coolant, it is important that use you only DEX-COOL' (silicate-free) coolant. If coolant other than DEX-COOL' is added to the system, premature engine, heater core or radiator corrosion may result. In addition, the engine coolantwill require change sooner at 30,000 miles (50 000 km) o r 24 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 wuter (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 else. -- Adding only plain water to your cooling system can be dangerous. Plain water, r some other o liquid like alcohol, can boil before the proper coolant mix will, Your vehicle's coolant warning system is set for the proper coolant With mix. plain water or the wrong your engine could mix, get too hot but wouldn't get the overheat you warning. Your engine could catch fire and or you Use others could be burned, a 50/50 mix of clean water and DEX-COOL@ antifreeze. 6-26