1998 Buick Regal Owner's Manual - Page 293

Adding Washer Fluid NOTICE: 0 0 0 Open thecap labeled WASHER FLUID ONLY. Add washer fluid untilthe tank is full. 0 When usingconcentrated 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 fluidtank and other partsof the washer system. Also, water doesn't cleanas well as washer fluid. Fill your washer fluidtank only three-quarters full when it's very cold. This allows for expansion if freezing occurs, which could damage tank if it is the completely full. Don't use engine coolant (antifreeze) in your windshield washer. It-candamage your washer system paint. and 6-29