How to wash a car

Posted on June 20th, 2016 by Rob Marshall


A survey by Simoniz revealed that over 40% of car drivers prefer to wash their cars at home. Yet, it is easy to damage your expensive-to-replace paintwork, by using either wrong products, or incorrect technique.

Here are GEM Motoring Assist’s top tips for washing your car in the summer, while reducing the risk of damaging the paint.

Never brush-off dust. Paint tends to get dusty in dry conditions, which is a mild abrasive. Avoid brushing dry dirt off with either a hand, or a cloth, because you are likely to introduce minor scratches to the surface. Soak and wash the car instead.

Trust professionals – Many opportunist car washers are uninsured and neither trained in technique, nor knowledgeable in how to use the professional products correctly, presuming that they are being used. While their services may seem to be a bargain, it is no exaggeration to state that hundreds of pounds’ worth of damage can be wreaked upon a new car, by a single poorly-executed wash. We recommend that you contact your local member of the Professional Detailers and Valeters’ Association, if you do not wish to clean your car personally.

Choose your timing. Washing cars in bright sunlight permits the water to dry too quickly and leaves marks on the paint. Dried shampoo will also cause streaks. Try to wash the car in cloudy conditions, or later in the evening. Avoid washing the car on loose gravel, or upon a very dusty surface, which will increase the risk of the paint being scratched, as it is washed. Remove any loose jewellery, such as rings, that will scratch the paint on contact.

Use the right products. Always use approved automotive shampoos. Never use washing-up liquid, which strips any protective wax form the surface and promotes corrosion through its high salt content. We would also recommend using a dedicated wash mitt, rather than a cloth.

Use plenty of water. While this recommendation cannot be followed in times of water shortages, no single professional detailer, with whom we related, recommends water-less car wash products. Apart from removing dirt, water acts as a barrier to prevent grime from abrading the surface. Start work, by washing off any loose dirt; using a hose for this process is ideal.

Top, down – Wet the car from its roof and work your way down. Follow the procedure, by applying warm water and shampoo together. This avoids picking up grit from the bodywork’s lower extremities, including the wheels, which could scratch the upper panels. Using a bucket with a grit separator is advisable.

Watch the motions – Wash across the paintwork and do not use a circular motion, which may introduce small round scratches, which professionals called ‘swirl marks’. Use lots of water and, after washing, have a separate bucket handy for rinsing.

Leaving to last – Wash lower body protection, mud-flaps and tyres last, as these plastic trims are more resistant to scratching than paintwork and are more likely to be dirty. Consider that brake dust is a particular hazard to alloy wheels, mainly down to small iron particles rusting and embedding themselves into the lacquer.

Dry – Do not leave the car to dry naturally. Use a suitable microfibre cloth to towel-down the paintwork. As when using your wash mitt, do not apply excessive pressure to the surface.

You have not finished… Consider that this basic wash process is only the beginning, as dirt is still likely to be trapped on the finish. We shall look at more advanced techniques in our next blog.