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Think Twice Before Adding Windex to your Windshield Wiper Fluid

A hand pours blue windshield wiper fluid into the car.
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Cleaners such as Windex helps keep glass clean, including your windshield, right? So wouldn’t it be a good idea to add some Windex to your windshield wiper fluid, also known as washer fluid, to keep it that way, or to replace your wiper fluid altogether with Windex? The answer is a resounding “no” on all counts, as this will damage many parts of your vehicle—including the glass.

Effects of Ammonia on Auto Glass

While Windex is a great product for the glass in your home, you shouldn’t use it at all on your windshield, even to clean the glass.  Many Windex products have ammonia, and may leave streaks on auto glass. This can pose a danger as it can create a glare while driving at night. It can also ruin your glass if it has been tinted, either from the factory, or as an aftermarket product.

The effects are even more damaging if you ever add Windex to your wiper fluid or replace it for your fluid altogether.  Windex includes chemicals that could damage the washer system, and contains chemicals that could damage the paint on your car.  Ammonia also dries out the rubber mouldings on cars, and could dry out the hoses that run from the washer fluid tank to the spray nozzles. It may even damage the windshield washer spray nozzles mounted on your hood over time. When your windshield wipers move to wipe the windshield clean after fluid is sprayed, the ammonia-based cleaner would end up on the delicate rubber windshield wiper blade and damage it over time.

Chemical Make-up of Washer Fluid

Let’s look at the chemicals found in windshield wiper fluid. These include Methanol and other types of alcohol, including Ethylene Glycol. Many also contain small amounts of ethanol (antifreeze) made from methylated spirits to keep the product from freezing during the winter.

The S.C. Johnson website lists Windex’s ingredients as water, 2-hexoxyethanol, isopropanolamine, sodium dodecylbenzene sulfonate, lauramine oxide, ammonium hydroxide, fragrance, and Liquitint sky blue dye.

One important distinction is that windshield washer fluid has an additive to keep it from freezing, while Windex does not. Neither does water, so don’t be tempted to top off your fluid with water to save money as that is also not a good idea.

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Function and Types of Washer Fluid

Windshield wiper fluid is for more than just keeping your windshield clean. It also lubricates the washer fluid pump, which is a very important function. If the pump doesn’t stay lubricated, it can stop working, leak and get corroded—none of which are good for your car.

When you activate the washer, the pump sends the fluid through a length of tubing that leads from the tank to just under the windshield. The process works the same if your vehicle has a rear washer as well.

Don’t get too caught up in which brand of fluid to buy, but you may want to consider the climate you live in. A general wiper fluid works well for warm weather. If you have cold winters, you’ll want to invest in a winter wiper fluid as these contain Methanol with Ethylene Glycol, a more powerful antifreeze. In those colder climates, a de-icing fluid is also a good choice.

There are other benefits of the ingredients found in wiper fluid—another reason to stick with these products. Some wiper fluids contain hydrophobic additives that can help rain bead off the windshield, while others contain extra-strength bug remover.

Changing the Washer Fluid

Now that you know what types of fluid to use and why it is so important, you should check it periodically. After, all, it is important to always make sure you have enough fluid to keep your windshield clean, as this is important to ensure your windshield’s visibility.

How to Check and Fill Windshield Washer Fluid:

  1. Make sure the vehicle is off and let it cool completely before opening the hood and moving on to the next steps.
  2. Open the hood and find the washer fluid reservoir—look for a white or clear container and it may have a symbol for the windshield or water. If you have rear wipers as well you are looking for two containers.
  3. Remove the cap and check the fluid level.
  4. Pour the washer fluid into the reservoir to the fill line or about an inch from the top of the container if there is no fill line.
  5. Replace the cap and make sure it is secured.

Correcting Problems with Washer Fluid

Perhaps you are reading this article after you added Windex or water to the container, instead of windshield wiper fluid. Here are some tips for correcting that situation.

  1. Make sure the vehicle is off and let it cool completely before opening the hood and moving on to the next steps.
  2. Open the hood and find the washer fluid reservoir—look for a white or clear container and it may have a symbol for the windshield or water. If you have rear wipers as well you are looking for two containers.
  3. Remove the washer fluid reservoir cap.
  1. Position a large open container, such as an oil drain pan, on the ground below the reservoir.
  2. Place pliers on the hose at the bottom of the reservoir and pull the hose straight down and off. Allow it to drain completely into the container below.
  3. Dispose of the Windex in accordance with local and federal regulations.
  4. After emptying the container, use a garden hose to spray water in the reservoir to remove any sediment left behind. Scrub the inside of the container with a toothbrush.
  5. When it is all clean, push the hose onto the bottom of the reservoir to reassemble then put the correct fluid into the container and affix the cap securely.

Keep all this in mind, the next time you go to replenish your wiper fluid. Your car and its windshield will thank you.

Please note, this article may contain links to Amazon products. As an Amazon Associate, earns from qualifying purchases.



Tara Taffera

Tara Taffera was the editorial director for USGlass magazine, AGRR Magazine , and Window Film Magazine. Her skills and more than 20 years of experience have helped her earn numerous journalism awards, including coveted Jesse Neal Awards. Tara enjoys spending time with her family and staying active with her husband by competing in races together, including triathlons. She also spends time volunteering in her community and with her church. Find out more about Tara on Linkedin.

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One Response

  1. A comment on your article above. I have been told by a number of glass suppliers to never use Windex on mirrors as they say it attacks the reflective coating at the rear of the glass, particularly around the edges.

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