1999 Chevrolet S10 Pickup Owner's Manual - Page 217

yellowblue How to Add Coolant to the Coolant Recovery Tank If you haven't found a problem yet, but the coolant level isn't at the ADD mark, add a 50/50 mixture of clean, drinkable water and DEX-COOLR engine coolant at the coolant recovery tank. (See "Engine Coolant" in the Index for more information.) NOTICE: In cold weather, water can freeze and crack the engine, radiator, heater core and other parts. Use the recommended coolant and the proper coolant mixture. CAUTION: 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 mixture will. Your vehicle's coolant warning system is set for the proper coolant mixture. With plain water or the wrong mixture, your engine could get too hot but you wouldn't get the overheat warning. Your engine could catch fire and you or others could be burned. Use a 50/50 mixture of clean, drinkable water and DEX-COOLR coolant. 5-13