Sprung a Leak

Last week on a particularly rainy morning commute I noticed a bead of water under my driver's side vent window. By the time I got to work it was obvious that the window was leaking. 

My dad and I replaced this window years ago because the original one wasn't functional. We did replace it with a junkyard find, hence all the rust, but I was still kind of disappointed. I looked at both surfaces that make the seal and everything looked ok but I guess the rubber was just tired.

These windows are great for getting airflow while driving since I don't have air conditioning, but the more you use them the looser they get and eventually just flop around in the wind. At that point I just stopped using them. Since I don't use this window anymore I didn't feel bad sealing it up with silicon caulk.