Here’s why washing your car with dish soap once in a while is OK and actually recommended sometimes.
We’ve all heard that car washing stereotype, using dish soap or dishwashing liquid as a car wash soap will ruin your car’s paint job.Embed from Getty Images
While there’s some truth in that, the supposed damaging effects dish soap has on your car’s paint preached by detailing diehards are often overexaggerated and unfounded.
It’s perfectly fine to use regular dish soap to wash your car if you don’t have car wash soap readily available.
What are we really cleaning?
Except for single stage paints on non-metallic paint colors, most car washing is cleaning off dirt and debris from the thick top-layer of car paint called clear coat.
According to Avalon King, the four biggest dangers to a car’s clear coat are UV exposure, chemicals, acid rain, and animal waste.
Except for sun, it’s the acidic nature of those contaminants that wreak havoc on your paint.
Bird droppings, for example, have a PH between 3-4.5.
Regular car washes remove these harmful contaminants from a car’s paint, preserving the protective layer of a car’s paint job.
What’s the difference between dish washing soap and regular car wash soap?
Both dish washing and car wash soap largely do the same thing, they disrupt the chemical bonds holding dirt and debris from a surface by forming a structure around that particle. And, when rinsed with water, the particles are safely removed from a surface.
What makes either soap different is its chemical composition and overall PH.
Basically, most listed active ingredients in dish soap and car wash soap are a combination of surfactants and foaming agents, both primary cleaning ingredients that give the liquid its dirt lifting and foaming properties.
While both liquids are mostly water (at least 90%) dish washing liquid has a higher concentration of dirt and debris-lifting ingredients since its purpose is to quickly and throughly clean off excess oils and hardened food from cooking pots, dishes, dishware etc.
Thanks to a higher concentration of dirt and oil-lifting chemicals, dish soap also naturally has a higher alkalinity raising the PH.
With a PH scale going from highly acidic to highly alkaline, from 0-14, you’d think dish soap is at the tail-end of the PH scale.
Here’s the PHs of Turtle Wax car wash soap and Dawn Dish soap, respectively,
On the PH scale, both soaps are classified as mild alkalies, not exactly PH neutral but with a neutral enough PH that shouldn’t be damaging to clear coat.
When choosing a car wash soap, ideally, you want to choose a product that’s as close to 7 (or PH neutral) as possible but still has enough surfactant concentration to clean and get the job done.
What’s the harm in using a dish soap?
As mentioned, dish soaps are powerful degreasers that will strip off any protective coating you have on, including that layer of paste or liquid wax (carnauba or synthetic.)
Without a protective layer, this exposes your paint 100 percent to harmful UV rays and contaminants. This can be especially detrimental if you have an older car with an already super-thin level of clear coat.
Then there’s that high PH.
If you choose a dish soap with too high a PH, left on too long, it’s possible said soap can damage clear coat finishes. Then again, we’re talking about if you’ve soaped your car, forgot it, and didn’t rinse off the soap.
Then again, looking at the PHs of dish soap and car wash soap, their PH levels aren’t that far off.
It stands to reason, when used like a regular car soap, its PH alone won’t damage your clear coat.
Here’s when you should use dish soap to wash your car.
First, if you DO have a car wash soap, use that.
But, let’s say you’re on a road trip, are stopped at your in-laws house and notice your car is caked in paint-damaging soot, bird droppings, and dust.
You raid your father-in-law’s garage and find no car wash soap. Rather than let that harmful layer of dirt and grime sit on your paint job, it would probably behoove you to use regular dish soap as car wash soap.
Diluted properly where it’s still strong enough to clean, it’s better to do a car wash now than wait till you get home.
When making your dish soap+ water mixture, a little goes a long way. Only a small dollop of dish soap is needed for a full bucket of water.
Also, if you’re going to apply a fresh coat of wax anyway, using dish soap, like Dawn or Palmolive, is probably the best way to prep a surface to receive a protective layer.
Dish soap, when used like a regular car wash soap, won’t damage your clear coat or paint and, in some cases has its place in your arsenal of car-cleaning products.
Just be sure to protect your paint with your favorite coating ASAP.
And if you don’t immediately apply a protective layer, it’s far from end of the world for your paint job, either.