View Full Version : Rear Window Water Penetration/Rust

05-21-2015, 12:50 AM
2006 T1N

I am in the process of addressing some minor rust at the bottom center of both rear windows. In order to prevent my repairs from succumbing to the same fate as the original paint, I am trying to understand how water was getting there. On the left and right lower corner of each rear window there are sizable weep/drain holes with openings *above* the sealant. These drains open into the door cavity, which then drains out the bottom of the door. These drains should theoretically catch any water that makes it past the seal on the top/side of the window or interior condensation that drains down the inside of the seal and migrates toward the center of the rear window. My drains were completely clear. So I am puzzled how water made it inside the seal AND then past these drains? All I can imagine is there was a leak in the seal on the top/side of the window and the sealant was slightly bridging these drain holes and allowing the water to run past the drains to settle in the middle of the window between the sealant and the sheet metal. There is no sign of sealant in the drain hole, so not confident the drain holes were blocked. I don't think condensation is the cause as I've never seen any condensation on the rear window.

All of my door seals are in good shape and the top of the door is basically a sealed unit, so there is no way for water to get inside the top of the door.

Does anyone have suggestions of things to check? Of course there will be new sealant when the windows are reinstalled. It would be convenient if the factory sealant application was the problem. The window removal tech did comment on how thin it was. I saw another post were someone commented about a sub par factory sealant application on the rear windows. Interestingly, it looks like if the sealant is applied too thick it could fully block these drain holes...which would be a problem. Perhaps this is why the factory application is thin?

I hope to avoid any discussion around how terrible the Sprinter paint is or whether it is due to lack of maintenance. I've accepted that I need to become proficient in rust/paint repair to keep this van which is built out with a great little camper set up :)