1997 Oldsmobile Silhouette Owner's Manual - Page 319

NOTICE: When adding coolant, it is important that you use DEX-COOL TM (silicate-free) coolant. If silicated coolant 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) or24 months, whichever occurs first. GM Engine Coolant Supplement (sealer) (GM Part No. 3634621) with any complete coolant change.If you use this mixture, you don't need to add anything else. -- L What to Use Use a mixtureof one-half clean water (preferably distilled) and one-half DEX-COOL (silicate-free) antifreeze which won't damage aluminum parts. Use TM Adding only plain water to your cooling system can be dangerous. Plain water, or some other liquid like alcohol, can before the proper boil coolant mix will. Your vehicle's coolant warning system is set for the proper coolant mix. With plain water or the wrong mix, your engine could get too hot but wouldn't get the overheat you you warning. Your engine could catch fire and or others could be burned. Use a 50/50 mix of clean water and DEX-COOL (silicate-free) antifreeze. TM 6-21