Headlining Removal?

[Sunny43.5]

It's a tar paper sort of stuff a very simple way for VW to cut down on roof vibrations and cuts down the tinny sound NVH it works but its a pretty piss poor amount , they also use it along the side walls as well .

[Gold Coaster]

Thanks once again Sunny.

[Gold Coaster]

Finally built up the courage to cut a hole in the roof of my T4 to put in a Fiamma Turbo 28 vent!



With this type of vent no drilling through the roof is necessary to attach it as it works on a sandwich type system whereby the outside upper frame and inside lower frame are screwed together from below thus pulling the roof and headlining together.

My question is whether or not I should add a timber support around the edge of the cutout between the roof and headlining so that as I tighten the screws it doesn't just keep pulling the two surfaces together too far to get a good seal?

On the other hand there is nothing in the installation instructions about having to do this so I'm thinking maybe it's because it is better to allow the roof to still be able to flex a bit around this area?

Any thoughts of this would be welcomed.

[Sunny43.5]

DO not install this the way they are telling you to !!! it will not work as the gap between the roof lining and the roof metal is not solid and it will leak like a ba%^&d . Okay you are right make up some timber spacers cut them as close to the distance between the two vent frames when they are screwed together . I would suggest assembling the two parts and then measure and cut the appropriate sizes you can glue them into place with some liquid nails . You have to get the right tension so that there is a constant clamping effect , I would suggest you use neutral cure silicone or urethane sealant DO NOT use ordinary silicone it has acid in it neutral cure is for metal roof and gutters . I fit sunroofs as you may know so the sort of job you are doing is very familiar to me , I would not allow the vent to be loose as you describe as that small a hole cut between the braces will be very solid . The only down side of a square hole is that the corners are the weak point if there was any flex in the roof the corners will be the first thing to start splitting that's why sunroofs have rounded corners it removes the risk . If you are needing any more info feel free to give me a call I,m the only sunroof fitter on the Google search for QLD

[Gold Coaster]

Thanks Sunny, I was hoping to hear from you knowing that you cut holes in car roofs on a daily basis.

I probably should have posted this ask earlier but luckily today I went with my gut instincts and put in the timber spacers and all looks good!

The sealant that the manufacturer suggested isn't available in Australia so I went with the closest that I could find which is a butyl mastic that reportedly sets with a tough skin but underneath remains soft. I thought though, in the worst case scenario, at least it would be easier to redo than if I had to rather than having used silicon.

The only thing that I didn't do that you suggested was to round the corners. At the time I wondered about this because the channel that the sealant went into was rounded but I went ahead and followed their instructions. Luckily though I added some extra mastic in these areas so I'm hoping that it will be well sealed.

[Sunny43.5]

Good on you for doing this unaided takes some b%%^lls to cut a hole in your own car , now pity you had not asked first about sealant as butyl would have ben the last thing I would recommended . The main issue with butyl is it dries out with time its the most hated sealant by us mob . Next the reason we use neutral cure silicone is that it has a life expectancy of 20 years and it works very good as it glues the outer frame to the roof which keeps it from moving butyl will allow movement and it will grind out the sealant as it dries over time . But hey what do I know it will probably be ok for the time you own the van so keep it as it is for now .

[Gold Coaster]

Yes Sunny, I was a bit hesitant about what product to seal outside of the vent with but I felt, as a first timer, that using a flexible mastic seemed a better option than using a silicon product in case things went wrong. In other words, if there was a problem then I could more easily remove the mastic and replace it with a silicon based product rather than vice versa.

Hopefully it will last awhile.

[Transporter]

You could always use Sikaflex brand sealant it's for the automotive use. As for the hole in the roof and right angle corners Sunny is right, it will start cracking from the corners. But you could still try correcting it by drilling the holes in the corners to stop the cracks, the 8mm or 10mm diameter should be sufficient and you will need to use some sacrificial sheet metal from both sides to void the drill bit from slipping.

[Gold Coaster]

You could always use Sikaflex brand sealant it's for the automotive use. As for the hole in the roof and right angle corners Sunny is right, it will start cracking from the corners. But you could still try correcting it by drilling the holes in the corners to stop the cracks, the 8mm or 10mm diameter should be sufficient and you will need to use some sacrificial sheet metal from both sides to void the drill bit from slipping.

As everything is in place now, including the wiring for the inbuilt fan, I’ll see things go over time. If I find that there’s a problem I’ll have a go at rounding out each corner a little as I would probably still have about 5mm that I could safely play with.

The manufacturer recommended a Sika product called Sikalastomer 712 but I couldn't find anyone who stocked it so I rang Sika. I was told that it's not available in Australia and the closest one to it was Sikalastomer 511, which was a mastic. Went to Bunnings to buy some but they didn't have any. The guy there rang Sika also and after speaking to him I chose the closest equivalent that they had which was Selleys Butyl Mastic. At $22.30 a tube I am hoping that it is a quality product as they other mastics there for around $7. I guess time will tell.

[Sunny43.5]

Selleys are good but its just the butyl is not so respected as other sealant types , you are partially right in saying its easy to remove as the silicone has to be cut with a Stanley knife blade . $22 for a cartridge is a bit steep in my opinion Sika products are premium and would be dearer but a Selleys at $22 no way . I would not get too concerned with cracking of the roof as you have not removed the roof braces and the hole is quite small but I would still check after 12 months or so and every now and then again after that , twisting of the roof on these vans is pretty rare unless the van had been used in extreme off road driving where you have one or two wheels off the ground crossing ruts etc .

[Gold Coaster]

All finished now! Thanks for everyone's advice, much appreciated.

[Sunny43.5]

Looks good all ready to hit the road , enjoy .