I purchased a Hyundai Ioniq 5 in April last year. On taking delivery of the car the gap between the wheel trims and the wheel arches was full with a white powder. I was told this was residue from the protective coating applied for transport. I was given an appointment for one week later to have this properly cleaned. A couple of days after the cleaning I noticed that the wheel arch trims had a silver/grey patina and also there was still some white powder in the joins, so I returned it to the garage, had another appointment and the car cleaned again.

After a few days the grey/silver patina reappeared on the plastic wheel arch trims, back to the dealer and a clean with a spray seemed to clear the problem. But it returned every few days and was more noticeable on the side of the car parked to the sun.

This was repeated several more times until the dealer informed me that I was not cleaning the car sufficiently and they then sold me a product called Meguiars Ultimate Black and said they would not do any more with the car until I had applied this product. As they product is sold as a plastic restorer I refused to apply it to a new car:

I then took my problem to Hyundai UK who have now proposed that they will paint the plastic wheel arch trims with a special paint, again I find this an inappropriate response to a problem on a new car.

I believe that the plastic is defective either because it has little or no UV stability or was damaged when the repeated cleanings to remove the white powder initially.

I would really appreciate your opinion and any experience you have on this problem.