1997 GMC Suburban Owner's Manual - Page 313

Adding Washer Fluid NOTICE: 0 0 0 Open the cap labeled WASHER FLUID ONLY. Add washer fluid until the tank is l-ill. 0 When using concentrated washer fluid, follow the manufacturer's instructions for adding water. Don't mix water with ready-to-use washer fluid. Water can cause the solution to freeze and damage your washer fluid tank and other partsof the washer system. Also, water doesn't clean as well as washer fluid. Fill your washer fluid tank only three-quarters full when it's very cold. This allows for expansionif freezing occurs, which could damage the tank it is if completely full. Don't use radiator antifreeze in your windshield washer. It can damage your washer system and paint. 6-31