You know I did exactly this with my drivers side window, but I just could not get it to work right. Either it was too loose, or whenever I got it tight, it would pull the rubber molding out of place at the bottom... There was no in between. I ended up scaring up the rubber pretty badly. i finally just gave up on it, got it tight and left it shut. If I ever try to open that window and re-shut it again, it will pull the rubber out of place.Airhead rider said:It's been written up a number of times if you care to search, the short answer is take off the door panel and look up where the lower post of the window goes in to the door. That lower post is a threaded post and it will have a spring, washer, and nut on it. You can tighten the nut that in turn applies more spring pressure to keep the vent window in position.
Others have taken out the rivet on the hinge of the vent window and replaced it with a bolt and nyloc nut, tightening it to apply tension.