1995 Cadillac DeVille Owner's Manual - Page 294

WINDSHIELD WASHER FLUID TQAdd When using concentrated washer fluid, follow the manufacturer's instructions for adding water. e Don't mix water with ready-to-use washer fluid. Water can cause the solution to freeze and damage your washer fluid of tank and other parts the washer system.Also, water doesn't clean as well as washer fluid. Fill your washer fluid tank only 314 full when it's very cold. This allows for expansion,which could damage the tank if it is completely full. Don't use radiator antifreeze in your windshield washer. It can damage your washer system and paint. 6-25