1997 GMC Safari Owner's Manual - Page 282

NOTICE: When adding coolant, it is important thatyou use only DEX-COOL@(silicate-free) coolant. If coolant other thanDEX-COOL@is added to the system, premature engine, heater core or radiator corrosion may result. In addition, the engine coolant will require change sooner at 30,000 miles (50 000 km) or 24 months, whichever occurs first. Damage causedby the use of coolant other thanDEX-COOL@is not covered byyour new vehiclewarranty. What to Use Use a mixture of one-half clean wpater (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, or some other liquid like alcohol, can boil before the proper coolant mix will. Your vehicle'scoolant warning system isset for the proper coolant mix. With plain water or the wrong mix, your engine could get too hot but you wouldn't get the overheat warning. Your engine couldcatch fire andyou or others could beburned. Use a 50/50 mix of clean water and DEX-COOL@antifreeze.