1998 Buick Century Owner's Manual - Page 285

What to Use To determine what kind of fluid to use, see "Recommended Fluids and Lubricants" in the Index. Always use the proper fluid. Failure use the proper to fluid can cause leaks damage hosesand seals. and Adding Washer Fluid Windshield Washer Fluid What to Use When you need windshield washer fluid, be sure to read the manufacturer's instructions beforeuse. If you will be operating your vehicle in an area where the temperature may fall below freezing, use a fluidthat has sufficient protection against freezing. Open the cap labeled WASHER FLUID ONLY. Add washer fluid until the tank is full. 6-25