Roof rail screw sealant?

Post by **FireFox31** » 16 Feb 2022, 18:43

What's the flexible black sealant used around the roof rail screws and their holes in the roof?

The sealant on my 2000 V70 was still soft. My new 2000 V70 uses similar sealant to hold blocks over the screw holes, still soft for firm yet easy removal. Thanks.

Post by **scot850** » 16 Feb 2022, 21:14

The bolts came with a small gasket for this. I would think you could use that black stuff you use for sealing gaps between inner and outer fenders. Kind of like a tar.

Neil.

Post by **MoVolvos** » 16 Feb 2022, 22:09

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Surebond-SB-188 T High-Temp Silicone Sealant, 10.3 fl. oz. Cartridge - Black

Posting not recognizing Amazon links at this time so here is the picture
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: Surebond SB188.png (138.82 KiB) Viewed 1103 times

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The air baffle box in the 2003 GS300 will all crack, disintegrate and in time split in half due to heat as it above the exhaust manifold. The car will have flat spots when accelerating from drawing excessive air. I used this to reattached both sections and to cover the box in it's entirety with it. Drys fairly fast to tack and will be rubbery when cured. Used in April 2020 and has held up and no flat spots during acceleration.

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Post by **FireFox31** » 16 Feb 2022, 22:34

Thanks, I see the gasket part 9178524 for $0.62 on the parts diagram. I don't remember seeing these when removing the rails from the donor car.

I just attached the image to the original post which I meant to earlier. Shows the black sealant spread down the threads of the screw since it was applied in and around the roof holes.

Navy · Post by **Navy** » 17 Feb 2022, 11:02

Dear Firefox31,
I have exactly the same problem. I removed my left rail to clean all the moss and debris which had collected and noticed the same soft tar like substance around the screw threads.
Anyway, I thought I would use roof sealant when the days are warmer but since then I found a large amount of water in the passenger (uk left side) under the carpet and soaked into the foam. Lots of water. Also, while driving I spotted a drip at the rear ( I think its a jacket hook) roughly where the tailgate pistons are located which had been soaking the floor.
I have used duck tape along the roof rail until the temp improves which has stopped the internal leaks.
I may try clear silicone sealant on the threads and under the roof rails. I've noticed bitumen based sealants tend to become brittle and crack.
Good luck and keep us updated.
Andre

Post by **scot850** » 17 Feb 2022, 15:25

If the water is leaking back there, do you have a sunroof? If so then it is likely a cracked drain tube from the sunroof. There is one either side at the rear of the 'cassette' and another 2 at the front corners.

It is possible the water is getting in past the roof rail seals if you did not re-seal them.

Neil.

Post by **FireFox31** » 17 Feb 2022, 16:39

Is silicon correct to seal the screw holes? I've used it in showers and it dried rather hard, thus might crack in the wide temperature range that a car must endure. My searches suggest that RTV silicon like Permatex 81158 can do the job.

The black sealant on the donor car's threads was the consistency of bubble gum, pulling off in strings. Seems like that low viscosity (compared to firm dried silicon) helps keep the holes sealed despite temperature and motion. Is that RTV?

Post by **abscate** » 18 Feb 2022, 10:57

Maybe butyl rubber type sealer?

Navy · Post by **Navy** » 18 Feb 2022, 11:02

FireFox31,
Clear silicone is my choice as I have used it elsewhere on my car and years later (exposed to uv) it is still flexible. I agree that some shower sealants (acrylic based) harden over time and the white silicone never seems to bond as well as clear. It's just my personal experience first choice and easily obtainable. Permatex81158 may well be a better product..keep me updated.

Neil, I had power stage and blower motor issues so with the glove box and knee bolster out I had good access. Also removed the trim on the centre post and around the tailgate piston. I was looking for either a internal leak from a overflowing drain on the bulkhead or from the seal around the windscreen/rubber seal around door. I had connected some thin tubing to a hose and flushed all four sunroof drain holes and even allowed the water to run for awhile I monitored the door seals and windscreen seal....Nothing leaked for 2 months until I was stuck in traffic in heavy rain and I noticed the drips from near the tailgate piston.
I figured when the car is parked on the road with a left side camber then water leaked in from the roof rail and either found its way under passenger carpet or in rear boot (trunk) space depending if facing incline or decline.
Placing gaffer/duck tape on roof rail solved all leaks. 3 months later and two storms later nice and dry but still need to seal those threads.

Sorry FireFox31 for going slightly off topic.
Kind regards
Andre

Post by **scot850** » 18 Feb 2022, 16:00

Good work on identifying the source. I had a weird leak on a 98 V70 XC. Could not figure out where it was soming in. Thought it was the sunroof or the drains. Again, it was when the car was at certain positions on slopes. Eventually a young apprentice mechanic at Volvo found that it was a bad seal on a replacement windshield fitted prior to my ownership. The sealant had been poorly done on the top LH corner and water got in there. Took it to a local windshield shop I use and they kindly removed the windshield and resealed it. No further issues.

Neil.