Auto body repair & detailing: window wind whistle, wind whistle, chevy g30

Question
I have a 1988 chevy G30 cutaway and the passenger side small tilt out window starts to whistle at about 35 mph. Is it the window or seal  around the window and how can i fix it please help

Answer
It is probably the seal and they are hard to change. Spray silicone on it real good to soften it up a little. Also, spray some penetrating oil on the upper and lower hinge and work the window back and forth to loosen it up. It could be binding and not closing all the way.