Car wash soap is one of the most common automotive detailing products on the market. This is a good thing because it is specifically formulated to clean your vehicle’s paint without damaging it. Even though it is a little more expensive than traditional dish soaps or laundry detergents, there is no real replacement for good car shampoo.
With a wider variety of these products on the market than ever, few people have an excuse not to wash their vehicle from time to time, even if it is their first time trying any kind of automotive work. But, the sheer variety on the market also means that not every car wash soap is a winner.
Shampoo formula can be very different from company to company, pricing can vary depending on what the product does and who makes it, and application can even be different depending on the type of soap you choose. All of this means that it is important to understand what differentiates a good car wash soap from an average one.
The Best Car Wash Soaps
The best options will contain a well-refined mix of ingredients which aim to produce a showroom-like finish.
1. Meguiar's Gold Class Car Wash
Meguiar’s is one of the most recognizable names in the automotive car care industry. They have been making quality car care products for over one hundred years, and their Gold Class Car Wash is potentially one of their best. The name says it all and reviews from those who buy it backs up its effectiveness and quality.
In addition to its gentle, high suds washing formula that can be used on top of wax without removing it, Gold Class also contains paint conditioners that leave a rich shine after the washing is complete. As a result of its all-in-one washing and conditioning formula, you will not have to spend extra time and money on additional products.
Gold Class also uses biodegradable detergents in their formula for those who are conscious of the environment. It can be used as a traditional car wash soap as part of a two-bucket car wash or can be used in tangent with a foam gun or foam cannon, further increasing its versatility.
2. Mothers California Gold Carnauba Wash & Wax
Mothers is another car care industry giant, and their California Gold Carnauba Wash & Wax easily plays back-and-forth with Meguiar’s Gold Class as one of the best and most widely used vehicle wash products on the market. Another versatile car shampoo, California Gold provides quite the bang for your buck.
Not only is California Gold a high suds, gentle car wash shampoo, but it is also formulated with natural Carnauba wax to provide extra shine once your vehicle wash is complete. This also means that it can be used as a wax booster and used over the top of an existing wax application. Its neutral pH means that it will not strip existing wax and that it is gentle on all paint surfaces.
Like Meguiar’s Gold Class, California Gold is also biodegradable and is more environmentally friendly than many other competitors. Once rinsing is complete, you will be left with a spot-free shine and a rich paint finish bolstered by its protective formula.
3. Karcher Car Wash & Wax Soap for Pressure Washers
Karcher Car Wash & Wax is specifically formulated to work with pressure washers, foam guns, and foam cannons, but the product is extremely affordable and works great for multiple applications. It is also safe for most surfaces to increase versatility.
It is both a wash and wax product, releasing dirt and grime with its high suds, phosphate-free formula, and applying a protective wax coating as it is used. Karcher’s biodegradable formula provides an added bonus for environmentally-conscious buyers and will leave no water streaking behind after rinsing takes place.
In addition to being offered at a low price point, Karcher Car Wash & Wax is highly concentrated, able to produce up to twenty gallons of vehicle shampoo with just one gallon of product, ensuring that you get your money’s worth.
4. Adam's Car Wash Shampoo
Adam’s products have made our lists before and for good reason. They offer a variety of vehicle detailing products and guarantee that their product will work and that you will love it with the promise that they will make it right if you do not.
Their car wash shampoo is not the cheapest, but it is multifaceted for full delivery on their promises. It can be used on many different surfaces, including plastic, rubber, glass, and vinyl, because of its pH-neutral formula; This also allows for more frequent car washing and washing over an existing wax layer or ceramic coating.
It can also be used with almost every vehicle washing application – two-bucket washing, foam guns, and foam cannons. One trick up its sleeve is the addition of a berry-scented fragrance infused within the shampoo to create a pleasant, clean aroma.
5. Rain-X Spot Free Car Wash
Rain-X is more well-known for its glass cleaners that make water bead up and run down a window without the use of wipers. For as satisfying as that can be, they also make a spot-free car wash shampoo that aims to do essentially the same thing.
Their highly-concentrated car wash shampoo allows for multiple gallons of soap to be produced for multiple vehicle washes. It produces a high amount of thick suds to remove and cut through tough dirt and road grime to leave a spot-free shine without damaging existing wax on paint surfaces.
The best feature of this product is that no hand drying is necessary. Rain-X’s unique formula includes rinsing polymers that create an ice-like hydrophobic surface that allows water to evaporate quickly and effectively.
How Does Car Wash Soap Work?
Beyond the obvious answer of, “car wash soap works by cleaning your car,” there are three general principles on which car wash soaps are built: penetrate, lift, encapsulate.
It may seem obvious that dirt penetration is the natural first step of car wash soap, but it makes sense. Unless the dirt is loosened and weakens its hold on the surface, it will not be able to ultimately be removed. Car wash shampoos are engineered to penetrate dirt on a microscopic level.
The second part of the soap's functionality is to lift the dirt off of whatever surface you are cleaning. High foam or high suds formulas excel at this since they provide both lubrication for paint scratch avoidance and dirt lifting power.
Encapsulation of the dirt particles – catching them in a suspension or carrier – is the last part of a car wash’s job and it is what takes the dirt away from the surface being washed. If car wash soap did not have encapsulation properties, the dirt would simply be shifted to a different part of the surface that was just cleaned.
Car Wash Soap "Metrics" and Terminology
As with any product, car wash soaps are labeled with, make use of, and display different buzzwords that help give information to consumers about what they are. Here are some of the most common more technical terms you might see on car wash soaps.
A polymer is a substance that is made up of large molecules. They can be synthetic or natural and are actually found in almost everything that you come into contact with on a daily basis. For car wash soaps, the word polymer is mainly used to emphasize a certain type of compound used in the soap.
Rain-X’s product specifically emphasizes a “special” rinsing polymer to emphasize that vehicle post-wash rinsing is not necessary. Many more products emphasize the presence of lubricating compounds to emphasize foam capability.
The measure of acidity or basicness of a car wash soap – or any compound – is its pH. Many modern car wash soaps emphasize a neutral pH level to demonstrate their ability to work on most surfaces. Vehicle paint and other types of materials can be fragile, so using a chemical with a very high or very low pH could damage it.
Soaps with neutral pH levels are usually less harmful to a wider variety of surfaces. The lower the pH, the more acidic a substance is. The higher the pH, the more basic a substance is. A neutral pH substance is a substance with a pH level of 7 on a scale from 0 to 14.
The term surfactant is not commonly used when soap specifications are listed on shopping sites, but it is common within ingredients lists. A surfactant is a compound that reduces surface tension when dissolved into another liquid.
Emulsification is another term that is quite commonly used in more technical car wash soap language. It is basically when two substances combine into one mixture without either dissolving. This is what happens during the encapsulation phase of a car wash.
Types of Car Wash Soap
There are really only two main types of car wash soaps: Single-purpose and multi-purpose soaps. Within these two types, many different subcategories are all made to perform different tasks for different types of washing jobs.
Single-purpose car wash soaps are the oldest type of car wash soap. It is what it says it is – a car wash soap whose sole purpose is to wash a car. They can wash cars in different ways, but there is no added functionality beyond its washing purpose.
Multi-purpose car wash soaps are like wash & wax products or those that wash, wax, and protect. These are engineered with additives that presumably do more than just rid a vehicle of dirt. For as great as some of these products are, they are often not as effective as single-purpose soaps since they have to try and do two or three jobs at the same time.
Things to Remember About Car Wash Soaps
Washing your vehicle is a pretty straightforward task, but even so, it is important to read the instructions on any product you buy. It could save your paintwork and prevent you from buying a product that may be optimized for a certain type of washing method that is inaccessible to you.
Regardless of what car wash soap you buy, it is important to use it correctly. The two-bucket car wash method is almost universally recommended by any detailer and/or automotive care company. Washing a vehicle this way will prevent scratching, ensure that only clean materials are used, and is the most effective way to wash a vehicle, even though it might take longer than an automated car wash.
Knowing what to look for, what you need, and some of the terminology used in the ingredient sheets and seller’s highlights will help you to buy the best car wash soap based on your specific needs.
As always, it is still important to read the instructions on each product since each requires different dilution levels, some are formulated for specific surfaces, and some are optimized for vehicle washing equipment that might not be in your possession.