After 40 years of owning roadsters there is one thing I've learned -- Don't take your car to a car wash. Seriously I have seen this issue with every roadster I have ever owned. It was worse in the old bays with side curtains rather then windows. Even the best ones I have owned all seemed to have leaked water over time even if I hand washed them. It could just be a window adjustment, etc. Good luck. I assume the car is NOT new to you. Tighted1 gave you some good links.