Why does the car paint change color after washing with self-cleaning detergent?
2 Answers
The reason for the car paint changing color after washing with self-cleaning detergent is that the paint is corroded by the detergent. Self-cleaning detergents have extremely high alkalinity and strong corrosiveness, which can affect the gloss of the car paint surface and even corrode the paint, leading to discoloration. Self-cleaning detergents are mainly used to clean stains on tires and rims. The self-cleaning detergents available on the market have very high alkalinity, falling into the category of caustic soda. Even when diluted to a ratio of 1:100, they remain strongly alkaline and highly corrosive. Using these detergents for car washing often results in damage to the paint, and they can also cause significant harm to both humans and vehicles during the cleaning process. Therefore, self-cleaning detergents can damage car paint and should not be used directly for washing cars; they must be used with caution. Cleaning power does not determine the quality of a cleaner. Cleaning is just one function of a detergent. The key consideration is whether the detergent can ensure that the surface being cleaned is not subjected to secondary damage while cleaning. The correct approach is to choose safe and environmentally professional car washing and detailing products and to avoid using corrosive alkaline cleaners or acidic cleaners containing harmful acids. It is best to repaint and repair the affected areas. Regular maintenance, such as applying a paint protection film, can also effectively shield the paint from damage.
After repairing numerous cars, I've found that paint discoloration after using self-cleaning car wash solutions is often due to overly strong chemical detergents, particularly those containing acidic or alkaline substances that react with the paint surface, causing pigment fading or whitening. If the concentration is too high or the solution remains on the surface too long, the corrosive effect intensifies, especially in high-temperature environments. Aged paint or surfaces with micro-scratches are more susceptible to damage. When encountering discoloration, I generally recommend promptly visiting a professional repair shop for polishing and restoration to avoid worsening the problem through improper handling. For regular car washing, it's safer to use brand-name detergents with neutral pH values, promptly drying the surface after washing and applying regular wax protection. In summary, prevention is far more important than repair.
