C220 noisy window
 

My 1996 C220 has 135000 miles. For years the driver side window has made a noise as it moves up or down. It sounds like the noise is from the glass rubbing against rubber seal. It has been making this noise for years but it's getting worse. It's time to fix it. Has one else had this problem? How did you fix it. Thanks in advance...

I once had this problem on another car so I cleaned and treated both of the rubber "squeegees" on the windows sills with rubber conditioner and the noise went away.

Yes, the rubber seal has become hard and no longer pliable. If you can put up with the film on the window from treating the part with rubber conditioner, that'll work for a while. Eventually, the rubber seal must be replaced.