1997 GMC Sonoma Owner's Manual - Page 268

Adding Washer Fluid NOTICE: a When using concentrated washer fluid, Open the cap labeled WASHER FLUID ONLY with the washer symbol on it. Add washer fluid until the tank is full. follow the manufacturer's instructions for adding water. a 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 washersystem. Also, water doesn't clean well as washer fluid. as a Fill your washer fluid tank only three-quarters full when it's very cold.This allows for expansion freezing occurs, if which could damage the tank it is if completely full. 0 Don't use radiator antifreeze in your windshield washer. It can damage your washer system and paint. 6-30