Why You Should Never Take Your Car to an Automatic Car Wash

Photo: Robert D. Barnes (Getty Images)

It’s springtime! Time to start working on your project car, learn a new wrenching skill, learn how things work under the hood, or just spruce up your daily driver. All month, we’ll be looking back at our best informative, maintenance and DIY articles from Jalopnik’s near 20-year history to get your ride ready for the road. Welcome to the Jalopnik Spring Tune-Up.

Every winter, it’s important to get road salt off your car as soon as possible if you don’t want it turning into rusty dust. The best way to do that is to just wash it all off, but heaven help you if you go to an automatic carwash. We spoke to an expert to find out why.

In case you missed it:

I must say this whole article was spurred by a conversation I had with Road & Track’s Sam Smith. Sam is a beloved and dear friend, a Jalopnik alum, and a Notorious Trickster Who Should Never Be Trusted. So when I proudly posted photos of my new-to-me Lexus going through the automatic car wash for the first time, I was utterly perplexed by his eloquent proclamation that “brushless no-paintfuck is a lie perpetrated by Big Flappywheel.”

G/O Media may get a commission

As elucidating as Sam can be, I wasn’t really able to decipher the reasoning for his rage through all the sniffles. The carwash was brushless, the sign before the big, gaping maw of whirring machines assured me. All of these fears were old hat, spurred on by the myths of yesteryear, I told myself.

I would proudly set my Lexus into its gentle jaws and be rid of the salty death chewing away at its metal underside. I was in the clear.

Or so I thought.

Photo: Michael Ballaban / Jalopnik

Wrong. At least according to Paul Lamberty, who is responsible for “all automotive OEM and refinish coatings research and development within North America” for BASF, a top-tier paint and finishings supplier to the automotive industry.

In short, Lamberty knows about paint, and he knows about how it reacts to going through an automatic carwash.

“It’s like painting your car with a wet sandblaster,” Lamberty told me over the phone. The problem isn’t really the bristles, he noted — it doesn’t really matter whether or not you automatic carwash is “brushless,” or if it uses bristles, or if it uses giant floppy foamy things to gracefully slop away dirt.

The problem is all of the crud, dirt and other “media” that clings to those brushes / bristles / noodles from all the other cars that ran through the carwash before you.

If the car before yours drove down a dirt road, for instance, it would pull into the carwash covered in mud and sand, Lamberty explained. Mud and sand are mostly made up of small bits of rock, including granite, which is extremely hard and abrasive.

That grit tends to stick to the cleaning apparatus of the carwash, which after a while can start to resemble sandpaper. “Some of those car washes, seriously, I’ve seen them where the brushes are gray to brown with dirt,” Lamberty told me.

With the high speed of the cleaning machines and the high pressure of the water, all that dirt and grit is rubbed along the surface of your car as it passes through — taking a little bit of your paint with it.

“I don’t care what car wash it is,” Lamberty said. “If it rubs that media on the surface of the paint finish,” your paint can be stripped away, he said. Eventually, your car could end up with what’s called a “spiderweb scratch,” which basically looks how it sounds.

Of course, if you’ve gone through an automatic carwash a couple of times, all is not lost, Lamberty reassured me. I didn’t have to throw my brand-new-to-me beloved Lexus straight into a dumpster. Virtually all cars come with some level of scratch-resistant clearcoat straight from the factory, which should provide some level of protection. It’s really only a concern if you take your ride to a carwash repeatedly, over the course of many years. And if your paint is only deformed, and not stripped entirely, it’ll probably go back to normal once a little heat is applied to it, even just from sitting in the sun.

And if you only plan on holding onto your car for a few years, it’s not something you’ll probably notice at all if you only go to the carwash every now and then. It’ll mostly start to look bad only after 10 years or more.

But, he cautioned, not all cars are the same. Most new cars come with an intermediate level of clear-coat protection, which should provide a good level of protection, he said. Some cars even have what he called “an advanced level of protection,” which “look as good coming out as they do coming in.”

So how do you know how good the protection is on your car? Well, that’s a much tougher question to answer, Lamberty said. Just because you get a high-end car doesn’t mean the manufacturer sprang for the higher-end paint protection at the factory. And even within a model, the level of protection can vary. Lamberty specifically pointed to the Ford F-150, which has different coatings depending on whether a particular truck was produced at Ford’s Kansas City Assembly plant in Missouri or Dearborn Truck Plant in Michigan.

“Both meet the manufacturer specification, but they’re two different coatings,” he said.

If you need to get stuff like salt off your car, just hand wash it, Lamberty said. Use a lot of water to get all the grit off your car gently first, and then maybe use a soft clay and some towels to make sure everything shines nicely.

Here’s a half-hour video you can watch if you really want to see how it’s done:

I then asked Lamberty if he’s ever taken his car to a car wash.

“Well, I’ve got 18 cars in my personal fleet,” he answered, “they range from a 1922 on up.” He considers a 1999 BMW M3 his baby, though.

“And I don’t think it’s ever seen a carwash.”