All The Differences Between Car Shampoo And Soap

So you finally managed to carve out some time to wash the car. You’ve got buckets, equipment… but still you are not 100% clear about the cleaning product, because the information on the internet is contradictory. In this article, you will find the main differences between soap and detailing shampoos for cars.

These are the main differences between car designed shampoo and soap like a dish wash or laundry detergent:

  • Level of pH
  • Foam quality
  • Exposure time
  • Lubrication
  • Concentration
  • Chemical composition
  • Paint exposure degree
  • Versatility 
  • Effect on car wax

Level of pH

The pH is used to indicate how aggressive the chemical is. A pH of 7 is a neutral zone; most car shampoos (especially for washing by hand) have a neutral pH. In practice, this means that they are quite harmless to car paint, just like special shampoos for children. 

Soaps, on the other hand, often have an aggressive pH. For example, most laundry detergents or the popular Dawn dishwashing detergent can “boast” a pH level of up to 9.3. This level of alkalinity is not only bad for your paint, but also for your skin.

Of course, there are alkaline shampoos, but they are usually formulated to minimize damage to the paint coating. Unlike soaps, which are designed to be aggressive and effective no matter what.

Foam quality

The foam produced by adding soap to water can be of lower quality than when using a special shampoo. The foam quality is determined by the size and number of bubbles, their vitality, density, and so on.

Check out this video about testing detailing shampoo’s foaming properties.

Generally, the larger bubbles are used to fight deep layers of dirt, while the more frothy foam penetrates the top layers of paint and removes primary stains. Shampoos combine both large bubbles and fine bubbles. Whereas soaps use either one or the other. As a result, the quality of the wash deteriorates. As a result, it can leave streaks and white spots on the paint.

Exposure time

When using soap, it’s very important to watch the timing of its effect on the paint. Usually, 2 to 3 minutes are sufficient, because longer contact will damage the paint. The product removes the top layers of dirt, but it does not always get to deeper accumulations like soot, bitumen, and so on.

With shampoos, the contact is usually longer, allowing the chemicals to penetrate deeper and “pick up” more dirt.


Shampoos include polishing agents that act as an asphalt roller. Imagine laying fresh asphalt on the road but not compacting it properly. The cleaning agents act as a paver, and then the polishing polymers finish the job. That’s how detailing shampoos work. 

Soap doesn’t work the same way. It’s a rougher method, without polishing afterward. Soap removes the surface layer and leaves nothing behind, exposing the paint to scratching.

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Shampoos are usually more concentrated than soaps. This is advantageous for several reasons:

  • Takes up less space in the garage
  • More cost-effective
  • Practical application

Soaps often have a more liquid consistency, which creates some inconvenience. When it comes to application, it’s easier to go overboard with the dosage of the liquid product.

Chemical Composition

Car shampoos differ significantly from soap in their composition. Shampoos with a neutral pH are used for washing by hand. They are so-called delicate products to treat chrome, polished aluminum, and plastic. They do not form an aggressive environment on the bodywork, and they wash away any dirt, thanks to the surfactants in their composition.

These chemical compounds (which are also part of household detergents) reduce surface tension, allowing you to easily remove dirt with a sponge or rag. Synthetic substances in car shampoos also act as lubricants, visibly reducing friction.

Soap is a completely different story. These are alkaline compositions with a high pH level tasked to dissolve dirt as quickly as possible. They achieve the result due to chemical aggressiveness, but not due to cutting-edge substances — they may not contain any.

Soaps contain neither friction-reducing lubricants, nor polishing agents, nor other components that make washing more convenient, pleasant, and safe.

Paint Exposure Degree

Car shampoo treats the paint safely, unlike soaps, which may easily ravage the clearcoat.

This is especially important if your car is not waxed. In this case, the paint layer will be affected immediately. Of course, the paint will not lose its shine and color in 1-2 washes, but over time, the detrimental effect of soap will be evident. Use car shampoo if you do not want to become a regular customer at a local car paint shop.

What should you do to protect paintwork during the winter? Not sure? Check it out for the answers!


There are dozens — if not hundreds — of types of professional shampoos. Each of them has its purpose, depending on the chemical composition. This variation allows you to adjust to any task without harming the paint at the same time.

Using soap, on the other hand, is something of an all-healing pill. You can wash your car with soap in any situation, but it will cause more trouble than good.

Generally, it is always best to use a dedicated cleaning product for the task at hand, if it is available. Cleaning glass with dish soap is not as effective, easy, and safe as cleaning glass with glass cleaner. The same goes for washing cars.

Use a dedicated car shampoo instead of dish soap in order to avoid damaging the paint.

Effect On Car Wax

Dish soap dissolves the wax layer, leaving no trace of it. Thus, after washing, your body will be “naked”. Sunlight, moisture, temperature – these are only some of the external factors that can damage the paint. You can also forget about the shiny and luxurious look of your body if you use soap.

Shampoos carefully “bypass” the wax layer and affect only the dirt. This effect is achieved due to the chemically active substances. After washing, your car will be safe.

Be sure to read the article on how important it is to wax your car.

Key Takeaways

  • Soaps affect paint much more aggressively
  • Car shampoos provide lubrication while soap does not
  • Soap is more likely to cause water spots after a wash
  • Most shampoos are wax-safe
  • Soap and detergents have a paint-dangerous pH

Here Are All My Favorite Car Detailing Products

Proper car detailing requires a lot of products. Given that the market for car detailing products is huge and there are many different products available, it can be very confusing and hard to find seriously high-quality products online.

I want to make sure that you as my reader get great car detailing products, so I decided to list my favorite products down below. I am sure you and your car will love them! 🙂

Microfiber Wash Mitts: Microfiber wash mitts are the go-to piece of equipment for every car cleaning enthusiast. Without a proper wash mitt cleaning a car is impossible. These are my favorites:

  • Amazon Basics Deluxe Microfiber Car Wash Mitt: Click here
  • Armor All Microfiber Car Wash Mitt: Click here
  • The Rag Company – Cyclone Wash Mitts: Click here

Car Shampoo: Car shampoo is the only suitable shampoo for washing cars safely. Make sure to get a high-quality car shampoo to prevent scratches. Check my favorites here and get yourself a good car shampoo!

Pressure Washers: If you are serious about car detailing and about cleaning your cars properly, there is no way around a high-quality pressure washer. I know that they are expensive, but trust me, a good pressure washer is a game-changer. Check out my recommendations below!

  • Karcher 13246440 K 5 Premium Full Control: Click here
  • Greenworks Electric Pressure Washer GPW2003: Click here
  • Karcher K1700 Electric Power Pressure Washer: Click here

Paint Protection: Paint protection is something that belongs to every car detailing routine. As it is so important, there are many different products and many different use cases. Check the list below to find my favorite paint protection products.

Jan-Lucas Ganssauge
Jan-Lucas Ganssauge