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Can I use dish soap to wash my car?

September 2, 2020

Many people grab some dish soap and hot water on their way out to wash their cars. Is this a mistake? Would you wash your own hair with dish soap that isn’t formulated especially for you? The answer isn’t so easy. We’ll break down the idea of using dish soap to wash your car.


The History


In the 1930s many people took their cars to the local service station so it could be washed and serviced. It was common to use the same product many times. In the 1950s, a product called Ethyl cleaner was popular. It was a dual-purpose cleaner marketed towards both men and women. It was marketed so that you could basically wash your dishes and go out to wash the car with the same thing. They didn’t have all of the new technology aimed especially at washing a car.


Difference Between Detergent And Soap


Dish soap is actually a detergent. It’s a high foaming mixture of different ingredients that don’t cause irritation to the skin. Detergents are actually different than regular soap because it does not form soap scum. Soap will react with minerals in water creating that thin layer of scum. The main ingredient in detergents, or dish soap, is water. It is then filled with dyes, preservatives, salts, and fragrances. Many people think because it has all of these ingredients it’s great to remove the dirt and grime in your car. Yes, it can. The problem is that it is not made for your car.


Liquid Dish Soap And Vehicle Paint


Liquid dish soap will not damage your vehicle’s paint or clear coat. The problem is that it isn’t ideal for general washing on a regular basis because it will slowly remove the car’s wax. If the dish soap has any abrasives that are meant for scrubbing, it might damage your paint, too. Wax and sealants on your car prevent corrosion. If the was is stripped, you lose shine and protection. If you are in a pinch, you can use dish soap. If you want to protect your car over time, steer clear of anything with detergents in it.


Surface Issues


If you think about it, you use a lot of water with your dish soap to rinse off those dishes. When you try to wash your car, it gets even worse. This is because of the compounds that lower tension between a gas and a liquid, called surfactants. These compounds may act as foaming agents, detergents, or wetting agents. They contain both hydrophobic and hydrophilic groups if you want to get scientific. This means if you use a strong surfactant formulation it will be very resistant to water. Dish soap

surfactant formulations are tough to remove. You’ll usually see streaks on the paint of your car when you use it. This is simply dried soap.


What To Use To Wash A Car


If dish soap isn’t the best thing for your car, then what can you use? Don’t look towards things like laundry soap or hand soap, or even household cleaners. These are not pH balanced. A specialized car soap has additional lubricant. It’s slick so it’s better for the surface of your car. You will need microfiber or sheepskin washing mitts. You could use one bucket for your soapy water and one for your plain water. You should use special tar and bug remover. Wax and polish are optional. Remember that not all car shampoos are created equal. We have a cheat sheet you should use when determining the best products for your car.


Ceramic Coatings


If you’ve applied a ceramic coating to your vehicle, you probably are a fan of the hydrophobic properties of the coating. It’s usually pretty easy to clean and doesn’t show water spots. You should use a car shampoo that is formulated especially for your ceramic coating. If you apply car wax on top of your ceramic, it will reduce your hydrophobic properties. You also need to stay away from shampoos that contain silicone agents because they can leave residue on your coating. A pH neutral shampoo is the gentlest thing you can put on your surfaces to remove dirt and debris. If you have a ceramic coating, it is already engineered to reduce contaminants from sticking on your vehicle. You don’t really need to use harsh agents or surfactants on it.


Wax And Sealants


If you’ve applied car wax or synthetic paint sealant to your car, you need a special car shampoo with certain ingredients. You should use a shampoo with a pH level of 7. You should also use a car shampoo with added wax or Silicone. This helps reduce scratching.


Using Polish And Wax


You can use polish and wax on your car if you do a few things first. It should only be used after you thoroughly wash the car then dry it with a specialized auto soap. The polish is used to make your car shiny. The wax protects your car’s paint. The water should create bead droplets on the car’s surface. If it does not, apply another coat of wax. Wax is only effective when it is used with the right kind of car soap. Some people get upset their wax only lasts a few weeks. You really need to only do a seasonal coat of wax if you are using car soap.


Do It Yourself


There seems to be a lot of rules when it comes to washing your car, so you may wonder why you don’t just take it t the automated car wash. These are okay if you don’t use them all of the time, but it is best to wash your car by hand. Automated car washes use large spinning brushes that hit your vehicle at a fast speed. These brushes aren’t usually rinsed between their cycles. The machine is spraying whatever it wants on your car. Those brushes might even put little marks on your coating that you can see in the sun. Of course, you can buff them out, but that’s not ideal for most car owners.


Final Thoughts


Your car won’t fall apart if you wash it with dish soap once or twice. It’s best to use a special wash made just for your car. Keeping your car protected will help it stay shiny and in top condition.