My four year old Chevy has two applications of ceramic coating (applied after clay-barring). Will an automatic car wash ruin or wear away the ceramic? Should one pay for the liquid wax on a car which has these ceramic coatings?
Everything wears away any type of coating.
This includes:
Washing by hand
Washing at a car wash
The sun, wind, rain, salt, snow, industrial and atmospheric pollutants, and just plain old time.
If you have any type of coating on your car - ceramic, wax, graphene- whatever, the best thing to do when you wash is to use a type of maintenance product to extend the coating. If you wash at a car wash - yes - get the ceramic, graphene, whatever they have. If you wash at home, use some type of spray sealant after you wash.
All coatings constantly degrade - all anyone can do to extend the life of the coating is to regularly use maintenance products to maximize and preserve the protection you have on your car.