Subaru WRX & WRX STI Manuals 2018 WRX & WRX STI Owner’s Manual | Page 504

11-38 Maintenance and service/Windshield washer fluid Remove the washer tank filler cap, then add windshield washer fluid until it reaches the “FULL” mark on the tank. If windshield washer fluid is unavailable use clean water. In areas where water freezes in winter, use an anti-freeze type windshield washer fluid. SUBARU Windshield Washer Fluid contains 58.5% methyl alcohol and 41.5% surfactant, by volume. Its freezing tem- perature varies according to how much it is diluted, as indicated in the following table. Washer Fluid Concentration Freezing Temperature 30% 10.48F (−128C) 50% −48F (−208C) 100% −498F (−458C) In order to prevent freezing of washer fluid, check the freezing temperatures in the table above when adjusting the fluid concentration to the outside temperature. If you fill the reservoir tank with a fluid with a different concentration from the one used previously, purge the old fluid from the piping between the reservoir tank and washer nozzles by operating the washer for a certain period of time. Otherwise, if the concentration of the fluid remaining in the piping is too low for the outside temperature, it may freeze and block the nozzles. CAUTION . Adjust the washer fluid concen- tration appropriately for the out- side temperature. If the concen- tration is inappropriate, sprayed washer fluid may freeze on the windshield and obstruct your view, and the fluid may freeze in the reservoir tank. . State or local regulations on volatile organic compounds may restrict the use of methanol, a common windshield washer anti- freeze additive. Use washer fluids containing non-methanol antifreeze agents only if they provide cold weather protection without damaging your vehicle’s paint, wiper blades or washer system.