BanksPhotos/Getty ImagesDriving for over 50 years, plus being involved in the auto repair industry as an ASE and General Motors Master Technician, I understand the essential value of windshield wiper fluid, especially when driving in icy, snowy climates. However, not all windshield wiper fluids are the same. Some have different freezing points, some are designed just to be effective for dust and road dirt, while others are better to clean bug splatter on long summer road trips.You can still buy a gallon of the standard “blue stuff” rated for temperatures above 32 F for around $4. However, if you can’t get to the supermarket or parts store to pick up a gallon of windshield wiper fluid, you can make your own with household items you probably have in your cleaning cabinet.Read along as an ASE-certified body shop manager and certified K-12 chemistry teacher share their expertise and practical tips to help you prepare a homemade windshield wiper fluid that will help increase visibility and your driving safety and comfort.Can You Make Your Own Windshield Wiper Fluid?Yes, making windshield wiper fluid yourself isn’t difficult or complicated and can be an economical alternative to commercial brand windshield wiper fluids. However, homemade windshield wiper fluid can cause damage or stain your car’s finish.AdvertisementAdvertisementAccording to Eric Heigold, ASE master technician and body shop manager, “It’s important to use the proper ingredients in the correct dilution [ratio of ingredients to water].” Heigold adds, “One part 70 percent isopropyl alcohol mixed with four parts distilled water is used to remove wax and other contaminates from paint [before repainting or waxing], so at the right strength, it’s safe to use [to make washer fluid].”ProsQuick and easy to prepareVery eco-friendlyMore effective cleaning of the windshield during harsh winter weatherYou can tweak the ingredients to meet your particular needs, such as adding more alcohol if you live in colder climates.ConsUsing “tap water can cause the wiper fluid nozzles to clog; think of mineral deposits clogging a steam iron,” says science and chemistry teacher Greg Feliz.According to Feliz, vinegar is a “weak acid,” and using other types of vinegar instead of distilled vinegar can stain your car’s paint or windshield.Using too much alcohol, methanol or denatured alcohol can stain your car’s finish or damage the paint.All alcohols, says Feliz, “are flammable and must be stored safely.”Pay attention to the ingredients when concocting homemade windshield wiper fluid. True story: It was snowing. My washer reservoir was empty, and the dealership where I worked was out of washer fluid. I needed something for the long ride home. Someone suggested using alcohol from the body shop. Mix it 50/50 with water, they say. “It’ll be fine.” Unfortunately, what I grabbed was full-strength, denatured alcohol. The following week, I found that the highly concentrated denatured alcohol mixture had completely stained the paint on the roof and hood, requiring an expensive paint job to fix.How To Make DIY Windshield Wiper FluidDIY windshield wiper fluid recipes are readily available. I have made this one myself, and it works as well as any ready-made fluid.Ingredients32 ounces white distilled vinegar96 ounces distilled waterThree or four drops Dawn dish detergent or a tablespoon of car wash/shampooClean one gallon jugBlue food coloring (optional)InstructionsMix all the ingredients well, then carefully pour into the windshield washer fluid reservoir.Test in an inconspicuous area (under the hood or inside the trunk) to ensure the solution doesn’t cause any paint damage or discoloration. “Rinsing off your car, no matter what type of washer fluid you use, will help protect the finish,” adds Heigold.NotesFor colder climates, cutting the vinegar to 16 ounces and replacing it with 16 ounces of 70 percent or higher isopropyl alcohol should offer freezing protection to around 20 F.According to Feliz, “Through the magic of chemistry, 40 percent methanol will prevent washer fluid from freezing where temperatures drop below -10 F. He adds, “Although the dilution ratio is relatively low, methanol is a strong solvent [and] proper dilution is important to decrease harming the finish.”Windshield Wiper TabletsWindshield wiper tablets are a great alternative to making windshield wiper fluid completely from scratch. They are small, making them convenient and easy to use and store.AdvertisementAdvertisementAlthough you’ll need to use distilled water and add alcohol for winter driving, they’re an inexpensive substitute that not only cleans dirty windshields but also makes good household cleaners due to their effervescent qualities. Usually, one tablet produces one gallon of windshield wiper fluid. This also helps reduce the number of empty plastic bottles that end up in landfills.Pro Tip: The best windshield wiper fluid will not make up for worn or damaged wiper squeegees. Also, in my experience, the windshield washer fluid reservoir is one of the most overlooked maintenance items in our vehicles. Replace it if there is scum, muck, or rust build-up that can clog or damage the washer fluid pump.About the ExpertsGreg Feliz, M.S., has a has over 15 years in industry, and an additional 20 years in the classroom as a Pennsylvania Department of Education certified K-12 chemistry, science and mathematics teacher and is currently teaching at Lansdale Catholic High School located in Lansdale, PA.Eric Heigold is an ASE and General Motors master technician, has been in the automotive repair industry for over 40 years as a technician, shop foreman, service manager and is the manager of Faulkner Collision Center in Philadelphia, PA.ResourcesCar Fluid Guide: “What Chemicals Are in Windshield Washer Fluid and Their Impact on Safety and Performance” (Oct 2024)Mighty Auto Parts: “Prestone All Season 3-1 Windshield Washer Fluid; Safety Data Sheet” (Jan 2019)John Stella, ASE certified technician is the senior bodyshop estimator for Faulkner Collision located in Phila., PA.; e-mail interview, Jan. 24, 2025
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