My 85 e150 has just a small place above the drivers door where the rain gutter has been fixed before. It looks like they maybe cut it out and formed a new one with a bondo like material as you can tell it when looking closely that it is not smooth. the area is about a foot long..
What i am seeing is a slight discoloration on the outside of the paint just under the repair like it is starting to rust under the repair...

I will try to get some pics posted in the next couple of days. For now though,, the aluminum band/channel/trim moulding, that they used around the high-top is almost right down on the rain gutter. There is only about an 1/8 gap all the way around the van so there is no access to make a repair without removing the aluminum moulding..

SO,,, earlier in a post about a rear side window leaking I learned about a flow-able silicone

I was wondering what you guys think about the idea of once I fix the place over the drivers door,,,, about using the flowable silicone all the way around the top of the van aluminum channel and the also the rain gutter. Putting it in the 1/8th gap between the molding and the rain gutter... Basically that would be closing off the gutter.

 

It is hard to envision what the silicone will fill. If it will keep water away from compromised areas it may be helpful, but if water is wicking in from some other area, it could make things worse by holding in moisture.

Frankly, most major parts added by van converters were not done with longevity in mind...lots of the side windows were put into holes cut into the van side and not rustproofed, so rust would bubble through the paint around the windows.

If the sheet metal that the high top is sitting on is compromised, that is not a good thing. I would spend some time poking the sheet metal (where it's not visible) with a screwdriver or other tool to make sure it is solid, and make sure that water is not getting there from some other source (through cracks in the top from the inside, etc.) I am wondering what caused a section of the gutter to rust based on what you are saying. Make sure the top is well secured around its perimeter and don't go tumbling down any mountainsides in your van...

My first 2 vans were Turtle Top conversions and when they got older, the fiberglass on the Turtle tops was badly sagged and cracking, letting water leak under the headliner and make the vans into mold pits. I'm a big van of low factory roofs these days.

George

 

Maybe it would be worth taking the headliner out and having a look. Right now it is too hot here to do much work except of the early mornings. The top appears to be in great shape but does have two skylight windows in the front. If one of those windows is leaking around the seal, I could see how water could be running down to the to the area in question.. . The other place perhaps could be the aluminum trim/molding that runs around the top..
Here is a pic of a similar type trim I am talking about
Heavy-Duty Insert Trim - White, 100' - RV Designer E461 - Installation Tools & Supplies - Camping World
I guess the aluminum trim screws go through the fiberglass and into the original metal van roof. If I removed the black rubber then I can get to the screws that hold the aluminum trim on.
In the mid to late 60's my father built the old wood frame aluminum covered camper shells to go on the back of trucks. I am vaguely remember it as my favorite job helping him was to put the black rubber insert inside the aluminum trim.. I was just a little one then!

I would guess there is a sealant under the aluminum trim. If I remove the trim then that wold give me much better access to that area. Between removing the trim and headliner I should have good access to find out what is going on. The only other place on the van body that needs attention is what
I believe is called "hood crowl seal"?, the rubber molding seal that seals the back side of the hood and makes rain water run of to the sides of the fenders.

This is just a pic of my project van I took a while back and not a close up of the area in question but gives you an idea what the body kooks like.

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