9 Major Differences Between Car Shampoo and Soap / Detergent

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.

Car Shampoo vs. Soaps

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.


Effective car washing means to clean the car as thoroughly as possible without damaging the finish of the exterior or interior.

That is why automotive shampoo offers a lot of lubrication for contact washes with a wash mitt.

This way the risk of scratching the car paint is minimized and car owners can wash their cars without worry.

Dish soap or detergents do not offer this kind of lubrication, as they are no car wash products manufactured for car care.

They are manufactured to kill viruses and bacteria from utensils or to remove tough stains from clothing.

To achieve this, dish soap and detergent contain more aggressive chemicals in them than car wash soap formulations.

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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 / Sealant

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.

Car wash shampoos and soaps 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 and the wax or sealant will actually perform much better again.

Can You Use Shampoo As Car Wash Soap?

No, you cannot use shampoo as car wash soap.

The two main reasons behind this are mainly that shampoo does not provide any lubrication and does not contain the right chemicals to to help break down grime and dirt.

The lack of lubrication means that shampoo is not safe for a contact wash. If you use it with a wash mitt, it will just scratch the paint of your car.

Also, using shampoo as a car wash solution will not lead to a good result as shampoo does not break down grime and dirt as effectively as car soap.

Car owners spend a lot of time taking car of their cars and they should make sure that car shampoos are used.

What Can I Use For A Car Wash If I Don’t Have Car Wash Shampoo?

If you don’t have car wash shampoo, there are still some options for washing your car.

You can start by simply washing with only water. This is the most basic way to clean your car, but do not expect great results with it.

If you have access to a pressure washer, make sure to use it. The pressure can remove a lot of stuck on dirt and will leave your car looking much better than if you were to only rinse it with water.

The only downside is that the absence of car wash soaps and shampoos will leave a road film on the car that you cannot remove with water alone.

Another option is Optimum No Rinse, which is a product designed specifically for cleaning cars without water.

This car detailing product was developed to be used without water and without the need for car shampoo or soap.

The downside is that ONR is quite expensive.

Finally, if you want an even easier option, you could try a touchless car wash. Make sure to not use any contact car washes.

A touchless car wash is the only category of car wash that you should use if you opt for using a car wash at all.

All other car washes are unsafe for cars and should be avoided as they are guaranteed to damage the surface of your car.

However, whatever method you choose, make sure not to use dish soap as it can be unsafe for your vehicle’s finish.

How Do You Make Homemade Car Wash Soaps?

Making homemade car wash soaps might seem like a great way to save money and keep your car looking its best.

But it is actually not recommended to make car shampoo yourself.

To make your own car wash soap, you’ll need baby shampoo, liquid soap, and water. None of these are safe for car cleaning except for water.

If you really want to risk your car’s paint and you don’t care about protecting your car’s finish, follow the following steps:

Start by mixing one part baby shampoo with two parts liquid soap in a bucket of warm water. Stir the mixture until it is completely blended.

If possible, add this mixture to your foam cannon and spray the car with it.

If you do not have a foam cannon, just wet a microfiber mitt with the solution and get to work!

Make sure to rinse off the soap thoroughly after washing as any residue left behind can cause damage over time.

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
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