Silicone is a BIG no!!! Can't stress that enough, it makes a shitty mess and never works or if it does for a couple weeks until it dries and then peels off from the roof, I hate doing these after some goon has siliconed it up!!
It's so easy to just do it properly, easy test is to 'tap' around the sunroof cassette where it sits on the metal work of the roof, you will see the roof of the car flex up and down under the plastic cassette, this is where it will be leaking. Renault used a stupid water soaking foam material to seal the cassette to the roof which obviously was dumb!!
Removing the complete roof is straight forward,
1. Remove the finisher around the sunroof headlining.
2. Remove grab handles and sun visors.
3. Remove courtesy light and courtesy light panel.
4. Pull back both front door seals around the A pillar and tops of doors.
5. Remove both A pillar covers.
You can now pull down the front of the headlining ( best to wind down both seat and put them right back )
You can now see a ring of 10mm bolts that sandwich the roof between the lower metal frame and the plastic cassette - remove these please!!
Once they are all loose you can push the sunroof cassette right out (easily) dependent on if some looser used silicone before!? Now use a powerfull jet wash on a concentrated jet and blast the old foamy seal away! Prob worth taking the glass out if it's a manual roof..
You need a mastic that will never set or go hard, it needs to stay flexible for the rest of it's life, Renault have such a mastic that is used on door cards and comes in a roll (fairly cheap) you need to stretch this all the way around the cassette where the old seal used to be, fairly central. The bead needs to be about 5mm wide and the same in height, make sure it's stuck to the cassette all the way around.
Clean the roof as best as you can I use a mild compound to get the heavy dirt of.
Then smack the cassette back in the hole it came out of, easier with two people the line it up. Give it a little push all the way around to squeeze the seal a bit. Next push up the lower metal frame and loosely screw in the 10mm bolts (give them a grease up first) then in a cross cross pattern nip all the bolts up (not too tight). You will see the seal start to squeeze out slightly and if you havn't uses to much mastic it won't squeeze out to far.
There you go, put back all the rest of the gubbins in reverse order. It wouldnt hurt to clean the rubber seal around the glass too, and lastly don't forget to push the drain pipes back
on to the cassette!! (forgot to
Mention those earlier they just pull off)
Now you