How much methanol is in a cup of -25F windshield wiper fluid if anybody knows lol. (:?
Most winter or de-icer labeled wiper fluids are mixed to contain at least 37% methanol. So 37% of 8 ounces 2.96 oz. meaning roughly 3 oz. of methanol is in 8 oz. (1 cup) of a typical winter wiper fluid. That said, many winter wiper fluids are only rated to -20F. which means they are either slightly less than 37% methanol OR are only rated to -20F instead of -25F because a 37% mixture of methanol and water has a freezing point of almost exactly -25F (actually about -25.6F). I'm not sure if this matters at all to you regarding this question or not, but if you want a fluid that comfortably resists freezing to at least -25F and you're making it yourself or something, you might want to use 40% methanol just to be safe (at 40%, the freezing point would drop down to about -38F, safely below -25F)
Most winter or de-icer labeled wiper fluids are mixed to contain at least 37% methanol. So 37% of 8 ounces 2.96 oz. meaning roughly 3 oz. of methanol is in 8 oz. (1 cup) of a typical winter wiper fluid. That said, many winter wiper fluids are only rated to -20F. which means they are either slightly less than 37% methanol OR are only rated to -20F instead of -25F because a 37% mixture of methanol and water has a freezing point of almost exactly -25F (actually about -25.6F). I'm not sure if this matters at all to you regarding this question or not, but if you want a fluid that comfortably resists freezing to at least -25F and you're making it yourself or something, you might want to use 40% methanol just to be safe (at 40%, the freezing point would drop down to about -38F, safely below -25F)
