1998 Oldsmobile Cutlass Owner's Manual - Page 239

What to Use Use a mixture one-half clean water (preferably of DEX-COOL@coolant which distilled) and one-half parts. If you use this mixture, won't damage aluminum you don't need add anfthing else. to NOTICE: I you usean improper coolant mixture, your f engine could overheat be badly damaged. and The repair cost wouldn't be covered by your warranty. Too much water in the mixture can freeze and crack the engine, radiator, heater core and other parts. If you have add coolant more thanfour times a year, to have your retailer check your cooling system. Adding only plain water to your coorrng system can be dangerous. Plain water, some other or liquid like alcohol, boil beforethe proper can coolant mixture will. Your vehicle's coolant warning system is set the proper coolant for mixture. With plain water or the wrong mixture, your engine could get too but you wouldn't hot get the overheat warning. Your engine could catch fire and you or others could beburned. Use a 50/50 mixture of clean water and DEX-COOL@coolant. I NOTICE: If you use the proper coolant, you don't have to add extra inhibitors or additives which claimto improve the system. Thesecan be harmful. 6-19