Here’s the situation: there are a bunch of threaded holes on top of the Transit roof. These threaded holes are used to install roof rack and such. If you climb on your Transit roof, you won’t find any of these threaded holes because they come with rubber plug and Ford simply painted over them. So let’s say you want to use the threaded hole, you would have to remove the paint and the rubber plug. We didn’t use any of these threaded hole so we left the paint untouched. Unfortunately, it seems that the paint cracks over time and as a result the roof leaks:
Here are the threaded hole locations:
It seems we’re not the only one having this issue: FordTransitUSAForum
After 6 months on the road, we noticed dripping water coming out of the wall over the sliding door; because our ceiling is insulated and finished, we could not locate the exact location of the leak. But we assumed it came from one of the threaded hole, so we climbed on the roof and we found that the paint was slightly cracked around the plugs (see previous picture). No big deal, we had some Silicone II in our toolbox and sealed the deal:
It’s a quick and easy fix. If you’re at the early stage of your conversion, you should probably seal the paint as a preventive measure. You could, for example, use the Dicor self-leveling sealant leftover from the roof fan installation (faroutride.com/fan-installation).
Note: if you’re thinking of sealing from inside the van, be aware that some of them are located under a frame and are not accessible… (source: FordTransitUSAForum).
Food for thought
Because we insulated our van using Thinsulate (faroutride.com/thinsulate-installation/), water found its way down; we were alerted of the leak immediately and we could fix the issue at the source. If we had use foam board or spray foam (or whatever), water would probably have been trapped and accumulate somewhere (remember some of the threaded holes are hidden within frames) and rust over time or drain all at once when driving and make a huge mess. Also, as opposed to denim or fiberglass insulation, Thinsulate is hydrophobic and don’t retain moisture; it will dry soon enough. We think that’s another good reason right there to choose Thinsulate (Buy on Amazon) for insulation…