Aww crap - leaky sunroof

[flutes]

It Rained in Sydney today.  Capital R Rained.

And this has demonstrated that I do, indeed, have a leaking sunroof.  Damnit.  I always suspected that was the case when I started looking into my water issues but never had any conclusive proof.

It looks like it's getting in under the seals and then coming down into the cabin through the roof - there were drips all down the front passenger seat back and the sacrificial carpet was wet in the rear footwell.  It was predominately the left hand side but this could have been because the car was parked on the left hand side of the street and was sloping down to the left.  Ir water could have been getting in all around the sunroof but then running down to the left hand side.

Looking from some advice here from more experienced peoples...

I'm 99% certain I need to replace the seals.  Autohaus list two products, a front sunroof seal, and a left/right seal brush.  I'm assuming I would need both of them, is that correct? Link.  Is there anything else I should be getting that I'll need?

Is there anything else that could be going on here that would need attention, aside from the seals?  I've read about the drainage channels, but could they be causing the visible water on the seat back that I saw?  How does one check these?

Thanks,
Matt.

[TJ 450]

Oh no,

Seals aside, it's rust, rust, rust you need to look out for.

The sunroof seals don't actually stop water penetration, they just prevent torrents flooding the inbuilt drains.

The things you should look out for are;

Rust in the frame gutters.
Blocked drain hoses (one in each corner).
A bad rear sliding panel seal that will allow water to flow onto the condensate pan area... water then floods the rear via the C-Pillars.

So, basically, the rear seal is the one that is probably most critical. The brushes won't make much difference and nor will the front seal. I would investigate what is going on before taking any action.

Step one would be to open the roof and inspect the far corners of the frame for debris and rust, then vacuum out anything that has accumulated... it may just be a blocked drain.

Tim

[flutes]

Thanks Tim.

Is there a diagram that describes how all this hangs together?  The shots in the manual don't really illustrate it very well.

[Jakob]

I don't have a diagram, but basically there are 4 drains, one in each corner. If you open up the sun roof, you won't be able to get a good look at the rear two drains, but you will get a chance to look at the front too. If blow out the front two with compressed air you should be able to unblock them (if they were blocked). After that, you should try and feel down the drains with a finger to see if  the metal part has rusted through.

That was the issue with my sunroof, the metal part of the drain that the rubber hose connects on to had rusted through and this was letting water leak through the holes, dripping on to the seat and running down the inside of the A-pillars.

[flutes]

What's the fix for that sort of issue Jakob?

[Jakob]

I hesitate to answer because since I had thought I fixed it I've noticed some more water in the footwells! It may be though that this leak is from another source that I have yet to find. I will have to spend a weekend pouring water over various parts of the car. It should be fairly easy to check if the it's the drains by opening the sunroof and pouring water very carefully only down the drains.

In my case there were only some small rust holes just before the rubber hose connects, and on one side the rubber hose had split.

I took off the headlining in the relevant areas (a bit of a pain to get back on afterwards. it doesn't match up now as well as it used to), and then scraped off the rust using a screw driver and a wire brush as best as the limited space allowed. After that I coated it in a some kind of rust remover that was hydrocarbon based and seemed to set as a sort of plastic coating, before epoxying up the holes and painting over the top with killrust primer and black topcoat. I bought some more rubber tubing, cut off the old tubing just before the split and joined the two via a hosejoin and some silicon sealant to give it enough length to reattach to the drain.

After that, I let everything dry and tested it by pouring water everywhere before reattaching the headlining (I seem to have lost some screws along the way as is always the case. I'm about to try calling the dealership to see if they can provide replacements!).

This is certainly not a permanent solution but short of taking the entire sunroof out (not just the sliding roof but everything, including unbolting the sunroof pan it from the roof.) and cutting off the rusty drains and welding some new ones on, or replacing the whole thing with a new sunroof pan, it's the best you can do. At least having a poke around in there will let you know if it is the drains that are leaking, or something else.

                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                     

[flutes]

Wow, thanks Jakob.  I'm going to be investigating that area this weekend.

Just as a suggestion - have you checked that your air conditioning drainage channels aren't blocked?  This was my primary source of water - see this thread

The condensation that should have been gong out under the car was goin down the AC ducting and running into the rear footwells.  It was quite a volume of water in the hot months as well.

[WGB]

Here is a picture of a sunroof frame removed from a car.



The left of picture is the front of the frame and you are looking at the underside of the frame.

The spigots that the drain hoses fit onto are visible (sticking out at an angle front and rear) and the rears end up starting about 1/2 way between B and C pillars and the trailing edge of teh fram can be felt thorugh teh headlining.

On this car the front drains were rusty and pinholed but the rears were OK.

The lower end of the rubber drains are visible either side at the front with the front doors about a 1/2 way height of the door skin and teh rears drain into teh rear wheel arches.

So long as your headlining is not too brittle it is not hard to remove the front overhead panel and sunroof side and front trim and ease back the headling where it is glued which will give you access to the lower surface of the frame and the front drains.

My rear drains have never had any rust problem.

Bill

[WGB]

I have taken some photois of my rusty frame to show where the problems are found.



This is the reverse side of the frame to the photo in the previous post and is the side that faces upwards.



Rusty Front left drain from top surface



Rusty front left drain from underneath surface



Rear left drain showing complete absence of rust - same on other side as well.

If you are doing a fix start by only worrying about the front drain areas.

Bill

[nathan]

you beat me to a pic, good one WGB.
i also second, third or fourth the check the drains. the most likely suspect.
not that i have pics as away from home lately, but the 126 sunroof is now safely nestled and functioning in the 6.9 resto! potentially a cheaper resto than finding a rustless 116 roof or having it repaired!
flutes, the drain holes at the front should be visible adjacent to your sunroof flap. try a small screwdriver to see if theres rusty muck in there (the vacuum sometimes does fit without a little attachment!)

[Big_Richard]

you beat me to a pic, good one WGB.
i also second, third or fourth the check the drains. the most likely suspect.
not that i have pics as away from home lately, but the 126 sunroof is now safely nestled and functioning in the 6.9 resto! potentially a cheaper resto than finding a rustless 116 roof or having it repaired!
flutes, the drain holes at the front should be visible adjacent to your sunroof flap. try a small screwdriver to see if theres rusty muck in there (the vacuum sometimes does fit without a little attachment!)

is that the early w126 sunroof (same as 116)
or the late w126 sunroof (fancy with additional movement)

? ? ? ? ?

[TJ 450]

Very nice, and descriptive pics Bill.

I've seen the 126 roof in Nathan's Goldy. It's a good fit, but it needs some minor custom fabrication to make it fit. It is the early version of the 126 roof.

FWIW, my 126 has an excellent sunroof frame. The car was towed straight out of a wrecking yard, so they are out there. The 6.9's is like new too, so you can be lucky, even with the original version.

My 450's sunroof frame has a lot of rust in the front corners that needs to be sorted out soon as well.

Tim

[flutes]

Thanks guys, and Bill, excellent photos.  I was having trouble visualising that before. I'll investigate on the weekend...

[Big_Richard]

I've seen the 126 roof in Nathan's Goldy. It's a good fit, but it needs some minor custom fabrication to make it fit. It is the early version of the 126 roof.

as per usual, Nathan only tells half the story 

[flutes]

So front drains "seem" to be clear, but I didn't get very much time to explore.  There could be a problem with the hoses.  Looking at the dried streaks of water that were there it may be the rear drains.  When I get more time next weekend I'll start by carefully pouring water down the front and see where it ends up.