Summer heat often makes washing your car difficult. Almost every car cleaning product label reads "Do not use in direct sunlight" and "Ensure surfaces are cool before use." Why is this written, what can happen if the instructions are not followed, and how can you wash your car during a heatwave?
Why you shouldn't wash your car in direct sunlight
With car cleaning products, the dwell time often plays an important role. In hot weather, liquids evaporate and dry quickly. The detergent needs to "sit" on the surface being cleaned so it has time to break down the dirt. If the product does not have enough dwell time, its effectiveness decreases, and the surface may not end up clean.
The biggest danger is the cleaning agent drying on the car's surface. Cleaning products often contain various acids and alcohol-based substances, and if the chemical manages to dry on the surface, it can cause damage.
The final danger is water drying on a clean surface. In Finland, tap water contains lime, which leaves white spots behind as it dries. Therefore, you should always dry your car after washing it – and dust will not stick to a dry car immediately either.
How to wash your car in the heat
Always check first that the surfaces to be cleaned are cool and the car is protected from the sun. If you cannot find shade, a good tactic is to turn the car so that one side is facing away from the sun, and wash it using cool water. Once one side is clean, turn the car and wash the other side. Wash and rinse one panel at a time so the car shampoo does not have time to dry on the surface, and finish by drying the car with a microfiber towel.
Read also: Washing your car at home and Thorough car wash.