Never use dish soap to wash your car.
You also shouldn’t use other household cleaning agents like hand soap or laundry detergent, or Windex on your car’s paint.
That’s our stance.
But read on for the science.
Regularly getting car washes or having your vehicle professionally detailed can easily cost a fortune, especially when you add up the costs year after year.
These issues often leave vehicle owners wondering what’s the best, safest, and most cost-effective DIY method for washing your vehicle at home. And makes you want to grab the dish detergent for a quick scrub.
Here’s why you should use car wash soap instead.
See Related: Washing A Car Without Water
Should you use dish soap to wash your car?
While you can do anything you want, I don’t recommend grabbing the Dawn dish soap to wash your car. Sure, it can get the job done, but the added salts and higher pH makes it a more caustic option that may damage your paint.
Choose a high-quality car wash soap that uses surfactants to life the grime out of the vehicle’s pores without harming the underlying paint.
If you have a stubborn area to clean — such as stuck on bugs — use a specialized orange-based remover instead of dish soap.
How About Hand Soap For Washing Your Car?
Not that hand soap is a highly effective cleaning agent, but it seems like it might be mild enough to get the job done in a pinch.
As with dish soap, hand soap has a pH of around 9.
The upside is that it might not have some of the salts in it, making it a milder option.
Plus, your car will smell like flowers when you are finished.
Explanation: Dish Soap Vs. Car Wash Soap
The chemical profile of dish soap and car wash soap is different. Car wash soap is designed to lift the grime without damaging your car’s clear coat. Dish soap is more abrasive and designed for maximum cleaning power but may harm finishes, especially when used.
Car soap should have a pH of 7 or neutral.
There are countless specialized vehicle cleaning products on the market, either available from local car detailers like Chemical Guys, big box stores, Autozone, O’Reillys or Amazon.
But are these car care products worth the money? Can’t you use household dishwashing liquid or laundry detergent to get the job done?
Sure, you CAN use these products!
But the real question is SHOULD you use dish soap to clean your vehicle?
How Is Car Wash Soap Different From Dish Soap?
At first glance, you wouldn’t think there’s much difference between hand soap, dish soap, laundry soap, or vehicle soap.
After all, they’re all designed to achieve the same result of cleaning a surface.
However, when you compare the chemical profile of these different products, they are vastly different.
1. Neutral pH
Car wash soaps have a lower pH, where dish soap uses a higher pH in the 8 to 9.5 range to help “dissolve” dirt.
This aggressive pH is also what can “dissolve” your clear coat.
Specialized car washing products are formulated with balanced surfactants to clean and polish the exterior without causing any damage to its paint job.
They should break down tree sap and bird droppings without hurting the finish.
On the other hand, dish soaps and other household detergents are harsher and more abrasive, accelerating the oxidation process. In other words, using these products can leave your vehicle’s exterior looking dulled since they’ll break down and wear away at the protective wax coating.
They can also dry out any rubber or silicone components, such as the weather stripping around your windows and doors.
Specialized car cleaning products contain foaming agents and other chemicals that achieve the same sparkling clean results without causing any damage to the waxed or painted surface!
2. Lubricating Additives
To prevent scratches, added lubricants are used in the formula to make car wash soaps more slippery. These help your sponge or car wash mitt glide along with the car’s finish.
When washing your car, these lubricants mix with the grime, encapsulating it and making it easy to rinse it off.
If you were to use detergent, this protective lubrication would be gone, meaning that you are “stripping” the grime and little bits of your finish off of the car.
3. No-Streak Easy Rinse
You should be able to easily rinse off the soap with no streaking.
Dish soap or laundry detergents tends to mix with hard water, leaving a spotty dry pattern on the car.
What About Using Dish Soap To Strip Wax?
Wax is designed to seal in and protect its paint from outside elements.
Dishwasher soap works great to strip this wax. However, it might also damage your car’s paint, which will leave your car’s surface vulnerable to oxidation and scratches.
That said, if you need to prep your car for a ceramic coating, you will need to remove any wax coating before applying the polish.
But there are many specialized wax removal prep products on the market formulated expressly to strip the wax without causing damage.
These prep products won’t be as harsh or abrasive to the paint, meaning you’re more likely to get a better-finished result than if you were to use dish soap.
What About Dirt & Grime?
All this being said, dish soap like dawn is a very good degreaser.
It will work to remove dirt and grime.
The problem, however, is that they will wear away the vehicle’s clear coat, leaving the painted surface vulnerable to damage.
In other words, although you can use dish soaps to clean your car, you’re better off purchasing an actual degreaser, which will be guaranteed not to cause any damage and will leave your car looking as clean as it can be.
Substitutions For Car Washing Soap
If you want to twist my arm and demand a substitute for car soap so you can wash your vehicle, here are my top picks.
- Hair Shampoo. With a pH closer to 7, hair shampoo is less likely to damage cars. Especially if you are just using it in a pinch, don’t expect amazing cleaning power, though.
- Baby Soap. Kid’s Shampoos are designed to be less likely to burn their eyes. It is also less likely to “burn” your car’s finish.
- Hand Soap. The pH isn’t ideal, but it should cause fewer problems than dish soap would.
- Dish Soap. Dish soap is less caustic than other household cleaners, so we’ll keep it on the list as a one-off solution.
General Tips On Cleaning And Detailing
While you are here, want some insider tips on how to wash your car as the pros do?
Here are some key car care tips.
- Start by first giving it a good rinse of water. This works to remove any dust and loose dirt that may be present on the surface.
- Then, you’ll want to mix your chosen cleaning products with water to create a soapy water mixture.
- After that, use a clean sponge or microfiber to suds up the surface of your car. Start with the top and work your way towards the dirty areas. The wheels tend to have more dirt on them.
- Then, use a hose or pressure washer to rinse away the suds, starting at the top and working your way down.
- Finally, use a clean chamois or microfiber cloth to dry the surface.
Bonus Tip: Always remember to clean your vehicle using a separate sponge or towel for cleaning around the wheels and wheel wells. These areas are often prone to picking small pebbles and dirt, which can get stuck in your sponge and then scratch up your paint job if you’re not careful.
Should You Use Polish And/Or Wax?
You’ll most likely want to polish and/or wax its surface to get that sparkling clean look we can all admire.
However, most folks are surprised to learn that there are differences between polish and wax.
That said, you want to polish your car FIRST before applying wax.
But what’s the difference between the two?
Polish helps to restore the shine, which can be dulled due to scratches and oxidation.
Essentially, using a car polish will remove grease, grime, and a very fine layer of paint, which helps minimize the scratches that can cause that dulled appearance.
Car polishes vary in terms of their abrasiveness, meaning that you’ll need to make sure you’ve purchased the correct polish.
Unlike polish, wax or clear coat is used as a sealant, which helps protect the paint.
Waxing your car gives it a protective coating, which will reduce the frequency and need for polishes.
You don’t need to polish or wax every time.
However, to keep your vehicle looking its best, you’ll want to do this at least once or twice per year.
Why We Don’t Wash A Hot Car
You’re not going to cause any significant damage by washing your car under the blazing hot sun.
However, experts recommend avoiding this because it will dry much quicker while hot, meaning you’re less likely to get the results you desire.
Washing a hot car that’s been baking under the sun often results in water spots and soap stains, which you can avoid by drying by hand.
Wax On, Wax Off: Removing Swirl Patterns
Swirl marks left on their vehicles after cleaning and washing them by hand are a major complaint.
Whether using carnauba or any other type of vehicle wax, these products can sometimes help remove any swirling patterns left behind by an inadequate cleaning job.
To properly apply a wax coating, start by dabbing or spraying on the wax product of your choice.
Then, use one side of a slightly damp microfiber cloth to gently smear and spread the product around on the vehicle’s surface.
Afterwards, you’ll want to use the other clean and dry side of the cloth to buff the surface until the surface shines and you’re left with no swirl marks whatsoever.
Always Rinse Before You Start
Experts always recommend rinsing before you scrubbing.
Rinsing the vehicle first helps to remove any loose contaminants, such as dirt, dust, and small pebbles, which can scratch and damage your paint when you’re scrubbing it.
Therefore, always make sure to rinse first, wash second, and then do a final rinse to finish.
Never Air Dry: Your Microfiber Towel Is Your Best Friend
Even if you’re using the purest water available, it will still contain natural minerals and other contaminants, which can harm your vehicle’s paint surface.
Therefore, the primary reason for never air-drying your vehicle is that these natural contaminants won’t evaporate and can leave unattractive water spots, deposits, and streaks on your vehicle’s paint.
On lighter-coloured vehicles, this is usually less noticeable. But for cars with dark-coloured paint, mineral deposits and spots are considerably more pronounced.
You will still get an excellent clean vehicle when you air dries your car. But you’re more likely to have a less-than-perfect finish when doing this.
For the automotive fanatics out there, the best way to avoid this is to use a microfiber cloth, mitt or towel, referred to as a chamois, to hand dry your vehicle.
A professional cleaner that is followed up with high-quality wax will help your car shed dirt, reducing the frequency with which you need to wash your car.