The T1N Sprinter van series was designed with an unfortunate configuration along its upper windshield seam.
|A picture tells a thousand words.|
|The gasket begins to peel back.|
|Ewwww. As soon as I saw this, I said to myself, "Well, my original plans for the day just went into the toilet."|
May I offer the obvious answer: Water penetration. Actually, only the driver's side degradation had worked its way all the way through to form a pin-hole leak. The passenger side looked bad but was still water tight.
I always wash and wax our Sprinter and I always encourage other people to learn to do the same. Every time someone on a forum gloats about having gotten a cheap and convenient truck wash, I wonder, "Yeah, but what incipient maintenance conditions might you have missed because you yourself were not examining your vehicle during that process?" This case in point is a typical answer. There is always something demanding attention with a large, complex machine.
And some of those things can get serious quickly if they aren't caught early. In our case, we are triply motivated to not let any condition like this get out of hand.
|We have a great deal of extra tech in our van, and a lot of the wiring for that tech runs down the driver's side pillar. Water in here is a bad, bad thing.|
Do you see the white twisty wire in the foreground of the photo above? That actually belongs to this device.
|...even shoving it up above the headliner...|
|...and then I mounted the noise-making end of the device under the dash next to the bluetooth on-board diagnostics (OBD) scanner. In case you're wondering why it's upside down, that's because the 9-volt battery is replaced via the "top" end which would be too difficult to access in this location if I put it rightside-up. This way I pop off the little flap and the battery falls out the bottom instead.|
|Being a POR-15 junkie, I first used a toothpick to coat the exposed areas, where the gasket had pulled away. I let that dry for about 4 hours. We had a beautiful 80 degree sunny day here, so 4 hours was more than enough time.|
This Sprinter Forum thread is not necessarily fond of using any silicone-like product around the windshield perimeter, but (a) I wasn't sure what else to use that I could obtain in sufficiently small quantities on short notice, and (b) I was only doing a couple of linear inches, so we'll just pay extra attention to prepping those corners in the future if we ever have to do a wholesale windshield replacement (there's some suggestion that a silicone product might interfere with a future sealant application during windshield replacement).
So there you have it, another chunk of a Sunday afternoon devoted to rig maintenance.
EDIT 20170321: See also this Sprinter Forum thread on this issue for further discussion.
|Actually, it never stops.|