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Seal crack caused by sunroof?

I have a 12 year old rebuilt Accord with a sunroof. At one corner, the metal roof is cracking and causing a hairline crack in the paint. It is beyond my budget and skills to get to the metal, weld it, repaint, etc. All I want to do is put some type of sealant over the crack to prevent water from penetrating. What would be the best product to use for something like this?

Waterproof silicone sealant.

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is “rebuilt” a “salvage title” ?

If yes, the crack may be due to some substantial damage repaired and now hidden under the layers of putty and paint, so it is likely that sunroof is only a weak spot, but is not a root cause of the issue

I would use a wax regularly, to keep water and salt out… and hope for the best

Get a caulking tube of automotive seam sealer at your local parts store that sells body supplies. About $20 but that’s what it is made for. But the crack must mean the car is coming apart. Were these two cars welded together?

Yes, it’s a salvage title, and I know the metal underneath is cracked. It actually creaks when I drive. But it’s not worth it to me to tear it apart to fix the metal, I just want to keep water out.

Thanks, Bing. I’ll give the sealant you recommended a try. Yes, I know for sure the metal is cracked underneath. And I don’t mind reapplying sealant periodically.

Thanks, Purebred. I’ll give silicone a try!

You know that car body integrity is compromised.
I hope you will use your best judgement to stop driving this car when it becomes unsafe.


That will work for a little while, but the crack will open up again. The only way to stop crack growth is the drill a small hole at the root of the crack to release the stress. If you drill the hole, the stress will be spread over the perimeter of the hole. If you don’t, the stress will be concentrated at the root (tip) of the crack, and the stress will be high enough to keep the crack growing over time. Fill the crack with silicone after drilling the hole.


Gorilla Tape.

… as long as it is better than Flex Seal Tape!
Unfortunately, I believed their TV advertising hype, and discovered that this stuff really doesn’t work.

The only thing to remember with using silicone is that nothing will stick to it again, not even more silicone. So no paint and if it cracks again, you have to get all of the old silicone off and clean the surface completely before another application of silicone can be put on. That’s why I don’t like the stuff for a lot of applications.

I don’t know what their TV ad’s say as I don’t have a TV but year;s ago when I first used gorilla glue & found out how good it was I checked out the tape & it worked on every thing I used it on & found it was as good as the glue.

Do yourself and family a favor…get rid of the car before it becomes a death trap.What do you think would happen to you and your passengers if the car rolls over due to an accident.The roof will collapse and you are history. No amount of caulking can fix this, believe me.


Would he be safer in a vehicle with a fabric top?

If this “rebuilt” car has an expanding crack in the roof where any buyer should have been expected to notice it, imagine what’s going on underneath where you aren’t looking.

I would at minimum get it into a body shop for a careful inspection. This could be very dangerous.

The nature of modern unitized body construction means that the roof is actually a structural part of the car. A crack in the roof indicates that this vehicle is probably no longer structurally sound.

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Where’s the picture of that truck that broke in two when they put it on the lift. Yeah the roof is the sheet metal skin. Underneath that is the structural supports for the roof. So likely they cracked first. Of course if it’s FWD, you can even cut the back off and still drive it dragging the rear. Demolition Derby?

You might recall that Chevy’s early ads for their new Citation model showed a Citation whose rear wheels had been removed and the back of the car was supported only by little “auxiliary” wheels.
For the folks who had–somehow–managed to be unaware of the existence of Toronados, SAABS, DKWs, and other FWD models, this served as an education… of sorts.