1997 Pontiac Grand Prix Owner's Manual - Page 297

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 else. TM NOTICE: If you use an improper coolant mix, your engine could overheat and be badly damaged. The repair cost wouldn'tbe covered by your warranty. Too much water in the can freeze mix and crack the engine, radiator, heater core and other parts. If you have to add coolant more than four times a year, have your dealer check your cooling system. ~~ 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 mix will. Your vehicle's coolant warning system is set for the proper coolant mix. With plain water or the wrong your engine could mix, you get too hot but wouldn't get the overheat warning. Your engine could catch fire and or you others could be burned. a 50/50 mix of clean Use water andDEX-COOL coolant. TM NOTICE: I you use the proper coolant, f you don't haveto add extra inhibitors additives which claim to or improve the system. These can be harmful. 6-27