Check on the roof to see that the little caps where the roof rack goes are still there and sealed - seven inches from the rear door is roughly the position of the 4th roof rack position I believe.
I have yet to solve my leak. Tried Teflon tape on the threads and that didn't work. Kinda hard to explain but my next step is to get some spacers the correct length and rubber washers.
I only put the racks on as needed so right now I have the holes plugged with short bolts, metal fender washers, and rubber fender washers.[/QUOTE
Teflon on the threads is pointless. The threads sit below the sheetmetal. Caulk (sealant) underneath and around the brackets for the roof rack or little plug when there is no rack should prevent leaking. I had a small leak after the roof rack installation at the rear left bracket even though I installed everything with sealant. Added some silicon, which fixed the problem. I don't like the Ford roof rack mounting system and nowhere in the rack installation docs does it mention to use sealant. You would think that the rubber pad would seal everything but it doesn't.
I haven't noticed any leaks in my 2016. There's five thousand miles on it since early July. That 5000 came because I did a 2 state ZIP code change. It's in the driveway, unless we go out of town.Not sure what's up with the roof leaks. I had one also. I took a wire brush and got up under the seam seal. A lot of dirt came out. I followed that up with a good acetone scrub and then sealed both sides of the seal with clear Dap gutter sealant. Now I'm just waiting for another heavy morning dew to see if I got it or not.
That came out pretty nice. I've got my leak stopped now but if it happens again I may just go the Linex route.Here is a look of the linex on the roof. The color came out slightly lighter than I hoped but I am quite pleased. As aforementioned, my van had a run in with a carport or a tree and needed some love up high. I will never have to worry about waxing the roof! Next asthetic project is the window tint with air 80 in the windshield.
Edit - the color is gun metal grey but looks tan in the pics. I was trying to match the grey plastics bits on the bottom of the van.