Does dish soap remove ceramic coatings?
Quick answer: No -- dish soap will not strip a properly cured ceramic coating, but it is too harsh for routine washing and can dull hydrophobic behaviour or lift a topper. Use a pH-neutral, coating-safe shampoo; if you have already used dish soap, rinse well and reach for a maintenance spray.
Dish soap will not remove a ceramic coating, but household detergents have no place on your car.
Dish soap is strong stuff. It is designed to cut baked-on grease from saucepans and casserole dishes -- It tends to be highly alkaline -- formulated around surfactants engineered to cut baked-on cooking grease -- and typically contains sodium chloride as a viscosity modifier, which is left behind as a mineral deposit on the paint surface as the suds dry. Even if the coating shrugs it off, the plastic and rubber trim around the car will not.
Plates and cups are often ceramic too, and you will have noticed how they dull and scratch over the years. Ceramic is tough and chemical-resistant, but repeated exposure to harsh cleaners and scrubbing takes its toll eventually.
We have had cars come in at the 9--10 month mark with flat hydrophobics and an owner convinced the coating has failed. The first question is always: what have you been washing it with? In a few of those cases the answer has been dish soap -- sometimes because car shampoo had run out, sometimes as a deliberate degreasing pass before a family event. The coating was still bonded; running a finger over the panel felt right. But repeated alkaline exposure, combined with salt content sitting on the paint as the suds dried, had gradually flattened the surface energy. A decontamination wash and a maintenance top-up sorted it each time. The coating had not failed; it had been washed into submission.
Car shampoo is not expensive and is formulated to lift traffic film and road grime without punishing the finish. That is what we always recommend. Dish soap can lift waxes and light sealants sitting on top of a coating (which will change how water behaves on the car), but it cannot break the chemical bond of a cured ceramic coating itself -- only mechanical removal by machine polishing does that.
For the broader "what shampoo to buy" answer, see what is the best shampoo for ceramic coatings.