Hello, I drive a BMW 3 Series E90 Built. 2005 Lim. without rear windscreen wiper. In the morning a thin film of water is always formed on the rear window and the view to the rear is virtually no longer there anymore. The same is true even if it rains. The water simply does not drain, no matter at what speed. I have already lubricated/polished car wax on the disc. Thus, something is blowing off, not everything and after 1-2 rain showers the wax was almost gone again. Can someone please give me a Ra t to give? Greetings Ben