1997 GMC Jimmy Owner's Manual - Page 237

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 SO/SO mixture of d ~ c t r z ,twtur (preferably distilled) and DEX-COOL'@ (silicate-free) antifreeze 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 mix. _s I 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 setfor the proper coolant mix. With plain water or the wrong your engine could mix, get too hot but wouldn't get the overheat you warning. Your engine could catch fire and o r you others could be burned. Use a 50/50 mix of clean water and DEX-COOL" coolant. 5-16