Sunroof seal orientation - which way?

[JKav]

Which way is the V-shaped rubber sunroof seal (901-564-905-05 - it sticks on the rear-most portion of the sunroof panel) supposed to be oriented? This is a 964 but I think all 911s are same design of this seal.

Should the open part of the "V" be facing forward? Or rearward?

The old seal was positioned (appears to be original!) with the V facing rearward:


The parts diagram shows the V facing forward:


Seems that either the factory messed up when installing the original seal, or the parts diagram is incorrect (I've seen errors in it elsewhere, so it wouldn't be a surprise)...

Which orientation is correct?

[john walker's workshop]

I put the V forward in hopes of trapping water and routing it to the drain trough on either side. Could be wrong though. The pic shows forward.

[Marc Bixen]

V- forward!

[JKav]

Upon a closer look, I think the direction the V faces probably doesn't matter either way.

What appears to matter more, though, is *where* on the sunroof panel the flat seal sits. All of the DIY installs I've seen place the seal very close to the velvet strip, which may not allow the seal to touch the chassis where it is intended to:



The "bump" feature at the trailing edge of the sunroof panel is probably there to tell you where to place the seal:

[Fairview]

Hi Jkav,

My 84 911 is original paint and was in storage since 2000, so I do not think the sunroof has been monkeyed with until I took it out this weekend to address a sagging headliner panel.

On mine the y seal faces toward the front of the car, and is mounted right next to the felt seal. You can also see a wide swath of factory adhesive, but no evidence of the seal having been mounted near the raised area at the rear of the sunroof panel.

[JKav]

Originally Posted by Fairview

Hi Jkav,

My 84 911 is original paint and was in storage since 2000, so I do not think the sunroof has been monkeyed with until I took it out this weekend to address a sagging headliner panel.

On mine the y seal faces toward the front of the car, and is mounted right next to the felt seal. You can also see a wide swath of factory adhesive, but no evidence of the seal having been mounted near the raised area at the rear of the sunroof panel.

Hmm interesting. Mine's a 964... maybe they moved the seal location rearward for 964. Can you see on your chassis where the top of the seal is intended to abut?

[Fairview]

Yes. Mine appears to be positioned so it sisters with the felt seal to keep water and dirt outside of the sunroof opening.

If you look back at my first photo you’ll see the edge of the y seal is dirty along the edge where the sunroof opening would be just aft of the felt seal. My guess is the y seal has two purposes, one to keep water and dirt out and second to direct water that does enter to the right and left to keep water from going straight back in the sunroof chamber. Does that make sense?

My car does have that ridge on the underside of the roof the you have photographed, but that is probably just a strengthening rib to keep the roof from flexing. I doubt Porsche wanted water going all way back there just to direct it to the right and left.

[JKav]

What's weird is my original V seal was situated away from the felt seal (can see it in the first post). This made some sense to me once I peeked at the car and saw the transverse rib at the corresponding location.

This would be less of a mystery if the factory service manual available online actually included the section for the sunroof...

[Fairview]

Originally Posted by JKav

What's weird is my original V seal was situated away from the felt seal (can see it in the first post). This made some sense to me once I peeked at the car and saw the transverse rib at the corresponding location.

This would be less of a mystery if the factory service manual available online actually included the section for the sunroof...

Yes, I see why you are wrestling with it. But it makes no sense to have a seal that far from the opening where dirt and water can enter. And it makes no sense to have a y shaped seal oriented so it would compress shut when water is flowing back toward the seal. Also, the factory parts book shows the top of the y facing forward. Plus in your photo it looks like the clear factory adhesive like mine is toward the front of the area, but your seal is glued on with a black adhesive, probably 3m weatherstrip adhesive, done later.

Unless there is another example of a seal positioned like yours, my vote for what it is worth, is to put it just behind the felt strip, y facing forward. On the other hand, it is probably academic as we avoid driving in the rain now that our 911s have gotten to be so valuable!

Hope some of this cogitation helps and doesn’t seem like meddling!

p.s. Also, Wayne Dempsey’s article confirms the seal position as described https://www.pelicanparts.com/techarticles/101_Projects_Porsche_911/85-Sunroof/85-Sunroof.htm

[JKav]

Another odd thing about this flat V seal is that is so short in height. The little flap on it sticks up hardly at all, so for it to effectively function as any kind of seal it would need a surface that comes down quite close to it. The only such surface (on my 964 anyway) on the chassis is the transverse rib. And even that surface may not reach down close enough to really engage the top of the flat seal...

Based on the state of all the various sunroof fasteners & related bits in my car, it sure looks like I'm the first to peruse this area. Same with the state of the V seal, dried and crusty enough that at 85k mi it must be original.