Doku Lupo 6X1 MJ 2001, Whistling noise at the doors (Solution)

High-frequency whistling noise coming from the doors.
Between 70 - 110 km/h, in the area of the side mirrors.

Cause:
There is a large gap between the window frame and the door glass in the area of the triangular section at the top.

Solution:
Remove the cover, starting from the top and gently prying it loose to prevent the retaining clips on the cover from breaking.
Loosen the fitting on the mirror base until the triangular piece at the top can be tilted slightly.
Insert the butyl cord into the darkly marked area.
Secure the mirror base and remove any protruding butyl rubber.
The butyl strip creates pressure on the window frame, ensuring that the gap between the window frame and the door panel is sealed when the screws are tightened.