As winter sets in, temperatures drop to below the freezing point of water and, as everyone knows, when water freezes it becomes a solid. Just about every driver knows the importance of adding anti-freeze to the cooling system to stop it freezing, but if the wiper fluid freezes, the results could be just as dangerous. A clear view through the windshield is essential for safe driving and requires the washer fluid to remain liquid even when the outside temperature is well below freezing.
Locate the wiper fluid reservoir on the vehicle. This is often located under the hood or in the trunk. If you don't know where it is, consult the driver's manual for your vehicle, or ask an experienced mechanic to show you.
Drain the existing contents from the reservoir by either activating the washers until the reservoir runs dry or by unscrewing the drain plug in the base of the reservoir and allowing the water to drain out naturally.
Establish the volume of a large container that can hold liquids and has an air-tight lid. For example, an empty gas can should have its capacity stamped on the side, and a large plastic bottle will often have the volume indicated on the label.
Determine the volume of methyl alcohol to add to water to form wiper fluid that will not freeze. If the lowest anticipated temperature is warmer than minus15 degrees Fahrenheit, then 35 percent of the fluid must be pure methyl alcohol. If the lowest temperature is above minus 40 degrees, 46 percent of the fluid must be alcohol, and if the temperature might drop to minus 65 degrees, 56 percent of the fluid must be alcohol.
Multiply the volume of the container by the required alcohol percentage to determine the volume of alcohol required. For example, when using a two-gallon container and producing wiper fluid that remains liquid down to minus 40 degrees use 0.92 gallons of alcohol, as 2 x 0.46 = 0.92. Likewise, if using a metric container, such as a one-liter bottle, use 1 x 0.46, or 0.46 liters of alcohol.
Add the volume of alcohol, calculated in Step 5, to the storage container, then top it up with fresh water. Seal the container and shake it gently to mix the two fluids.
Refill the wiper fluid reservoir from the storage container, as required.
