1993 Buick Park Avenue Owner's Manual - Page 226

How to Add Coolant to the Coolant Recovery Tank If you haven't found a problem yet, but the coolant level isn't at or above "FULL COLD," add a 50/50 mixture of clean water (preferably distilled) and the proper antifreeze at the coolant recovery tank. (See "Engine Coolant'' in the Index for more information about the proper coolant mix.) In cold weather, water can free IA I CAUTION: Adding plain water to your cooling system can be dangerous. Plain water, or some other liquid like alcohol, can boll befare the proper coolant mix will. Your vehicle's coolant warning system is set for the groper coolant mix. With plain water .of the wrung mix, 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 mix o Glean water and a f proper antifreeze. I I I