1999 Buick Regal Owner's Manual - Page 270

yellowblue 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 to use the proper fluid can cause leaks and damage hoses and seals. Adding Washer Fluid Windshield Washer Fluid What to Use When you need windshield washer fluid, be sure to read the manufacturer's instructions before use. If you will be operating your vehicle in an area where the temperature may fall below freezing, use a fluid that has sufficient protection against freezing. Open the cap labeled WASHER FLUID ONLY. Add washer fluid until the tank is full. 6-30