Windshield Washer Fluid

Part 1 of the Essential Fluids Series

Windshield washer fluid is one of those things you usually do not think about until you are driving and some mud or bird doo hits the one spot on the windshield that blocks your view. If you are out of fluid, your wiper blades just smear the mess. How frustrating! So, let’s take a look at when to check your fluid, what fluid to use, and a few tips for the winter months.

Photo by LoboStudio Hamburg on Unsplash

Photo by LoboStudio Hamburg on Unsplash

When to Check Your Windshield Washer Fluid

Most vehicles have some sort of sensor to tell you when the windshield washer fluid is low.  This is great, but I do not rely on this completely.  If I am driving, especially on the highway, and decide to clean the windows, it could be just enough to reduce the amount of fluid in the reservoir to make the low fluid light come on. I would rather not have that happen.  I usually check the windshield washer fluid every other time I put gas in the car. So, if I put gas in the car four times a week, I check the fluid twice.

I also check the fluid when it’s cold, and there is a chance of snow. Usually, the snow hits the warm windshield (after the car has warmed up) and dries instantly.  This calls for using more windshield washing fluid than normal.

Checking the fluid is quick and easy. Refer to your owner’s manual for details and instructions. Usually, the windshield washer fluid is in a readily accessible place under the hood. Just remove the cap and fill with your choice of windshield washer fluid.

What Windshield Washer Fluid to Use

In the winter and spring months, you will see mountains of windshield washer fluid displays at every gas station and home improvement store. Most types of windshield washer fluid are basically the same.  Most contain methanol to keep the fluid from freezing.  You should know that methanol is poisonous, so be careful. Make sure your pets don’t lick up an spilled fluids.

For this reason, some people like to mix their own solution.  In the summer or hot months, you can actually just use water, but only in a pinch. Water does not clean the oil and gunk from the road very well. It will also freeze if you forget to change it in the winter.

If you choose to use water, distilled water is probably best.  You can also mix distilled water and rubbing alcohol (isopropyl alcohol) together for a homemade version that won’t freeze.  You can use about one cup of 90% (or higher) alcohol per gallon of water.

Honestly, it’s often less expensive to purchase the commercial windshield washer fluid. As to what brand or color, that’s purely a matter of choice.  I don’t think there is much difference between the different brands, but you might have your favorite.  Some may also contain more or higher concentrations of methanol or alcohol and therefore might do better in colder temperatures.


One important tip is to make sure the nozzle where the fluid comes out is clean and not clogged with snow, dirt, or mud.  When clearing snow and ice from your windshield before driving, make sure the fluid has a clear path from the nozzle to the windshield.

Finally, when it is freezing outside, and your windows are covered with ice, you can use the windshield washing fluid to clean your window and melt some of the ice. But, be careful. If you are driving, the windshield will likely freeze up again, making it hard to see.  It’s best to scrape the ice off of the windows and let the car heat up a bit before driving.

Written by Gary Pradel