How to Wash Your Car in the Sun: 8 Essential Tips


We’ve all been told that we should never wash a car in the sun, but sometimes it’s unavoidable. This is the case whether you’re a mobile car detailer, or just live in a hot climate and want to clean your car!

In this article, I’ll be running through 8 tips to help you wash your car in direct sunlight. So let’s get started.

The Quick Answer

Washing a car in direct sunlight should be avoided, but if this is not possible then here are 8 tips to help wash a car in the sun:

  • Use pH neutral chemicals
  • Try using a rinseless or waterless wash system
  • Get all your chemicals and tools prepared before starting
  • Keep spritzing the car with a mist of water
  • Work one panel at a time
  • Turn the car around halfway through the wash process to keep it in the shade
  • Wash the car in the early morning, or in the evening
  • Use a drying aid or quick detailer spray afterwards

Let’s take a look at each tip in a bit more detail so you get the best from them all.

I have also made a video on the Auto Care HQ YouTube channel with some more summer wash tips.

Use a pH Neutral Shampoo and Prewash

One of the main issues with washing a car in direct sunlight, is strong chemicals drying on the surface which can cause staining if left to sit and bake onto the paintwork.

Using a pH neutral car shampoo is the best way to reduce the risk here. Alkaline and acidic products are much more damaging to the paintwork (especially when left to dry) compared to pH neutral products.

Of course, you need to do your best to make sure that no chemicals dry onto the paint during the wash process, however, it’s far less likely to be an issue with a pH neutral shampoo.

Luckily, most car shampoos are pH neutral. Generally, a lot of prewash products, such as citrus prewash sprays and snow foams are slightly alkaline. So try and pick a prewash product that is pH neutral instead.

They’re likely to have less cleaning power than alkaline snow foams and prewash sprays. However, if you live in a very hot climate then the car is less likely to be dirty than if you live in an area with bad weather, so it shouldn’t be too much of an issue!

Try Using a Rinseless/ Waterless Wash Product

If the water is evaporating too quickly on the car and leaving unsightly water spots, then your best bet is to try a “rinseless” or “waterless” wash solution.

One of the most popular options, is Optimum No Rinse. This is very simple to use and a lot more suitable for hot climates than traditional car shampoo and water.

Here’s how to use it:

  • Pre-rinse the car to remove any loose dirt
  • Add 1 oz of Optimum No Rinse to 1 gallon of cold water in a bucket
  • Soak a microfiber towel in the wash solution and use it to wipe the car down in a straight line motion
  • Keep flipping the towel to make sure you aren’t wiping it with a dirty section
  • You’ll probably need at least 5 towels per car to do this as safely as possible
  • Dry the car as normal using a clean, dry microfiber towel

Optimum No Rinse is a hugely popular option and claims to be a safer alternative to traditional car shampoo in terms of reducing the risk of inflicting scratches and swirl marks during the wash process.

Get Everything Prepared Before Starting

Time is of the essence when you’re washing a car in the sun, so that the chemicals and water don’t have time to dry onto the surface. Getting everything prepared before you started helps make the wash process far more efficient and really reduces this risk. Here’s a quick checklist of things to get prepped.

  • Fill your wash and rinse buckets
  • Make sure your pressure washer is connected and ready to go
  • Have all your chemicals (car shampoo etc.) ready to hand
  • Get your drying towels nearby
Kärcher car wash

Keep Spritzing the Car with Water

Again, the main thing you need to avoid, is water and chemicals evaporating on the paintwork. So the best thing to do, is to keep spritzing the car with water to make sure the panels are wet throughout the entire process.

Use a spray, or fan setting at a reasonably high pressure, as opposed to a hose pipe which produces water at a low pressure. Low pressure water will encourage the water on the paint to “sheet” off the surface. The aim is to keep the panels wet, so “spritzing” it is the best option here.

Work One Panel at a Time

Working one panel at a time is the best possible way to avoid the dreaded water spot issue. Of course, this technique will take much longer. But the results are well worth it.

You don’t always need to work every single panel separately, but splitting your car into main areas such as the roof, hood, rear, left side and right side is a good idea.

When you do this, you should rinse, prewash (if necessary), rinse again, shampoo, rinse, and dry each area completely separately. You may need to go over the car again at the end with a microfiber towel to catch any water which has spilled onto other areas, but it’s a great way to avoid water spots.

Turn the Car Around Midway Through the Wash

If part of the vehicle is in the shade, then make sure you position the car facing the shade as much as possible and wash this area first. Once you’ve done, jump in the car and flip it around.

Of course, this option isn’t always possible if the sun is coming from pretty much everywhere, but it’s well worth the slight bit of extra hassle if you can do this. It’ll definitely help to reduce water spotting and chemicals drying and leaving behind stains which not only look ugly, but can damage the integrity of the paintwork.

Try Washing the Car in the Morning or Evening

If you live in a hot area or are working in the middle of Summer, then avoiding peak sunlight hours is essential. The sun is at it’s highest point at midday, making it the hottest part of the day, and the most difficult to try and find some shade.

So try and choose your moment wisely and always wash your car as early as possible in the morning, or just before dusk to make sure you’re taking advantage of the coolest parts of the day.

Use a Drying Aid Afterwards

If you’re trying to wash your car in direct sunlight, then even if you’ve followed all the tips above, then you can still end up with some pesky water spots afterwards.

Using a drying aid, or quick detailer spray to remove these can be a really useful solution. Koch Chemie FSE Quick Detailer and Optimum No Rinse (mixed 1 part product, to 16 parts water) are great options here.

Both can be used as drying aids or quick detailers. If you’re using the products as a drying aid, then give the paintwork and your microfiber towel a quick spray before wiping each panel to dry it.

If you’re going for the “quick detailer method”, then dry the car as normal, then go over the car with the quick detailer afterwards by spraying the product onto a cloth and wiping the affected area, then flipping to a dry side of the cloth and buffing away the residue.

Issues With Washing a Car in the Sun

Okay, so those were the 8 tips to help you wash your car in the sun. However, I still need to stress that this should be avoidable if at all possible, because washing your car in the sun isn’t recommended.

So why is it a bad idea? Two main issues can occur when you wash a car in direct sunlight:

  • Water will evaporate onto the vehicle and cause water spots
  • Cleaning chemicals will dry onto the car and cause staining

Both the chemicals, and the water spots can cause long-term damage to the paint, especially if they aren’t quickly removed and are left to bake onto the paintwork in the sun.

They cause what’s called “etching” which means that the top layer of paint effectively becomes corroded and wears away. So it definitely needs to be avoided!

If you absolutely can’t wash your car on a cooler day, then make sure you follow the tips above, and remember the golden rule, don’t let any chemicals or water dry on the car.

Thanks for reading! I hope you’ve found this article useful. Here are some other articles you might find helpful.

Heather

I first became interested in car detailing around 3 years ago and learnt all the main techniques on my very first car. I spend a lot of time detailing my current car, and trying to keep my family's cars looking presentable too!

Recent Posts