Sealing Sunroof


What’s the easiest method to seal up the sunroof after removing all of the actuating hardware and rails? We are trying to get my father’s car ready to go. His sunroof is too rusty to re-use. Rather than rivet a piece of sheet metal over the hole, I’d prefer we weld in an OEM unit. Anyone have a spare they don’t need?


I riveted a panel over the hole and had automotive caulk between the panel and the roof. Why do you not want to rivet a panel over the hole?


If riveting a piece of sheetmetal on top is too ghetto for you, slap some faux carbon fiber tape on it. Stay classy baby.

Alternately, if there’s enough structural integrity left in the old sunroof panel, separate the two layers of sheetmetal and then sand/paint the outer layer. Then install. Or put the carbon fiber tape on it and install.


I can make cf moon roof skin if your interested. Won’t be cheap or se30 legal.


Just weld a piece of sheet metal in. Thats what we are going to do with my sunroof and then we have a piece of vinyl that is the same color as the car to put over it. Just an idea you might want to think about.


I struggled with the ghetto-pop-rivet-panel thing too but ultimately did that. Honestly, once it’s painted to match the roof it’s hardly noticeable and far easier to install and seal than using the original sunroof panel.


My buddy is a hell of a fabricator… He took some 1/4 inch rod and cut it into 2 inch chunks… Then we held the oem sunroof top in the hole. Carefully tacking the chunk of rod on the corners of the rod to the roof, then the sunroof panel.

Then we maneuvered the rod into position lining the sunroof panel in the hole square (tricky but effective). Then we spot welded 5 more chunks of rod into place.

The original roof panel is in place and looking almost oem.

The 1/8th inch gap around the sunroof and roof I filled with Marine grade caulking. I got it to stay in place by using duct tape on the underside to hold the wet caulk in place until it dried.

After it shrank back a little in 2 months, I re-caulked…



My car just got a piece of flat sheet metal welded in the hole. Its hard to tell it does not have the exact crown of the roof unless you really look close.


My car also just got a flat sheet of metal welded in the hole. They didn’t do a very good welding job and managing the heat, but nothing some sanding and body work can’t fix eventually. I just threw a quick coat of rustoleum on it. I went that way because like the OP my sunroof panel had rust holes in it and instead of trying to fix the holes on that thin sheet metal I went with a new sheet.


After welding the sunroof hole in and then doing the body work to smooth everything for two cars, I say it is not worth the effort. Pop rivet a piece in and go racing.


Are new collision repair roof panels available from BMW? I am thinking about cutting the roof off to install the roll cage and to save the cost of fabricating a new roof panel or pop-riveting a piece of “tin” up there.

I have not acquired a car yet. I’m at the just looking at this class stage after 5 years of TaG Karting.


There’s a few guys in the southeast who have cut off the roof to install a cage then reattached, so you might want to talk to them about the experience.


Are you asking about an entire smoothtop roof panel? A new rear quarter was about 700$. A new roof must be double that if even available. Plus you would have to redo several hundred spot welds and a few braised seams. You wouldnt be able to get a new roof complete with pillars and internal sturcture. You would need to find a smoothtop 318 in a junkyard if you want that.

I asked the shop where I got my logbook how they had room to tig weld their cages and they said they cut holes in the floorboards and then raise the cage up to get it tight to the roof. This seams like a better idea than cutting off the roof to me.