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I’ve seen countless articles listing washing up liquid and other household detergents as alternatives to car wash shampoo. But should you use these to wash your car?
No, you shouldn’t use washing up liquid, shampoo or household detergents to wash your vehicle. Car shampoo has been formulated to be gentle on your car’s paintwork.
In particular, a pH neutral car shampoo is best as it will wash off dirt without impacting any wax.
In this guide, I’ll explain how the chemical make up of these household cleaning products impacts their performance on your vehicle, plus my favourite car shampoo.
Why Can’t I Use Washing Up Liquid on My Car?
Despite what many forums may tell you, washing up liquid such as dawn or fairy is not a suitable alternative for car shampoo and shouldn’t be used to wash your vehicle.
It is usually formulated using a hydroxide base added to liquefied plant or animal fat. This creates a highly alkaline formula which is great for tackling the tough dirt that accumulates on your dishes. However, it’s not suitable for your car.
Remember that most of your dishes and kitchen utensils are made from either ceramic or stainless steel, whereas your car has a top layer of thin plastic over the paintwork called the clear coat.
These are very different materials and need to be treated as such.
If you have applied layers of wax to your car, the washing up liquid will remove these as well, leaving your car’s paintwork without protection from the sun and removing the glossy finish.
A proper car shampoo has been designed to leave wax on, this is thanks to a pH neutral (or close enough) formula.
Which Hair Shampoo is Best for Car Wash?
Hair shampoo is far more suitable for use on your vehicle than washing up liquid, although still not perfect.
Hair shampoo and car shampoo both tend to utilise Sodium Lauryl Sulphate as a key ingredient.
The best hair shampoo for your car is baby shampoo, this has the mildest ingredients and should do a good job of cleaning your car without removing any wax.
Baby shampoo also tends to be pH neutral which is best for your car.
However, I’d still recommend car shampoo as the best option as it has the optimum level of foaming and tends to be made with distilled water which removes many of the impurities in the water that could cause white water spots.
What’s the Best Car Shampoo?
I recommend Autoglym Bodywork Shampoo as the best car shampoo available in the UK.
It has a pH neutral formula and has been designed to form a glossy water barrier which allows you to rinse with ease.
It is a low foam solution, and the highly concentrated formula means a bottle will last a long time so it’s not very expensive per wash.
What Household Products Car I Wash My Car With?
All of the detergents in your house have chemical formulas that have been optimised for the task they are intended so there is no great alternative to car shampoo.
If you are in desperate need of an alternative, then baby shampoo is your best bet.
This has some of the same base chemicals as car shampoo and is very mild so won’t cause any damage.
You should avoid anything that is powder based such as laundry detergents or homemade car wash soap with baking soda as many websites recommend.
If the powder does not dissolve fully, it could scape across your vehicle during the wash and cause damage to the clear coat.
How Do I Wash My Car with Just Water?
To answer this, it’s worth understanding how car shampoo works. Like many cleaning products, it’s made from a surfactant which has a head (hydrophilic end) and tail (hydrophobic end).
In a simplified explanation, the head will bond to the water and the tail will bond to the dirt particles, this reduces the surface tension and helps lift the dirt.
As you can see, the shampoo plays a key role. Whilst you could remove surface dirt with just water, you won’t be able to get the deeper dirt particles without a cleaning agent.
Tips for Washing Your Car
Here are some more helpful tips for an effective wash:
- Make sure to use the correct equipment. Using improper equipment such as those big yellow sponges or a bath towel is a common cause of scratches.
- Instead, you should opt for a proper wash mitt for washing and a microfibre cloth for drying.
- Try not to wash your car on a sunny day or in direct sunlight. The heat will cause the car to dry before you have chance to properly dry it yourself.
- Wash from top to bottom and dry from top to bottom.
- Add a layer of wax afterwards, it’s actually a lot easier than you think, it adds protection against the sun’s UV rays among other benefits.
Kieren is the founder and editor-in-chief of Auto Adviser. Kieren created the site to share his passion of cars that began long before he passed his driving test and is now a recognised contributor in the industry. Outside of cars, Kieren loves drinking coffee and travelling to far-off lands.
