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PostPosted: Mon Jul 24, 2017 1:57 am 
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Joined: Mon Jul 29, 2013 6:44 am
Posts: 1148
Location: Azusa,CA
Been in discussion recently with some G8 guys and a Caprice owner on FB who are experiencing pools of water in their floor / carpet. This is usually after a rain storm. Source has been narrowed down in some cases to a poor seal on the vapor barrier at the bottom of the door. I will go into how this system works and remedies that can be employed.


Evidence
So first you must determine if your leak is coming in from the door at all. As you know our cars with lots of holes drilled in them in their life we could have multiple sources for leaks. For another thread where some leaky culprits were found check the thread on Water Leaking Into Interior.

These pictures are from a G8 owner and this evidence is the key indicator that something is wrong with your vapor barrier in the door. You could probably see this evidence after a good long car wash as well. He wrote:

Every time it rains, the floor behind the driver seat is wet. Right now, the only lead I've got is these two things. There is water in the groove in the weatherstripping on both driver side doors, along the red lines, and drips in the yellow circle under the driver door.

Image Image

These are from a Caprice owner and if you see water dripping off the interior side of a door that is a dead giveaway:
Image Image

In fact where the 3-4 door drains are located the only place you should see water that has drained from the door is along the outer part of the door sill and on the painted top of the rocker panel. Green line in below picture illustrates where acceptable water would be:
Image


Investigation
So first lets look at the entry point as that might be a secondary thing to get fixed along the way. The horizontal exterior window seal is where the water comes into the cavity of the door. The doors are designed to have water get in them through this seal. Because the face of this seal is felt (has to be to let window slide past it when going down) standing water on the tip of it will just migrate through the seal. The water that gets though the first seal is caught by a secondary seal that has a U channel in it that should direct it to the front or rear of the door (depending if you are pointing up hill or down hill) and drop it down the outer ends of the door cavity (away from window motor, regulator, wiring). On the G8's these outer window seals have been know to deteriorate, so we got that to look forward to. Make sure yours is in one piece with no holes and it is making contact with the face of the glass when the glass is fully rolled up. Here is a side shot of a window seal in good condition you can see the first and second seals.

Image

So if these seals are in bad condition replacing them won't fix your problem as water is designed to get past them. But fixing them may stop the quantity of water that the vapor barrier has to deal with and that will become important with the remedy we discuss next.

Next step is to get a look at the vapor barrier. That means taking off the door panel. Will see if I can link to a good description on how to do that. But once you get it off you want to one, confirm you actually have a vapor barrier, that may have been removed in the decommission process for some reason. If you have one make sure there are no tears in it in the lower part (top part has holes for wires and door lock cables but those are to high to let any water through). If it looks in good condition turn your attention to the butyl rubber seal along the bottom or the vapor barrier where it meets, sticks to the door. What you might find here is it has come detached from the door or it has a kink in it that creates a channel that would allow water past it. What I have determined, which is amazing, is that this seal is supposed to hold water back. In other words they designed it to collect "some" water. Not sure I care for that. Hate having standing water next to metal.

So here is my bottom door seal. Looked to be in good shape.

Image

I have removed it a few times to do various mods. Always just sort of stuck it back on there not giving it much thought. But then I started to look closer at it and what I saw was micro debris. That is either silt or rusted metal shavings that seem to have been transported there in water then left behind once the water evaporates from the space. It was all along the bottom of the seal. So the conclusion I came to is some water gets held here and if the seal was bad it would come down the into the interior of the car.
Image Image

Being curios and having the outside window seal removed for that picture I though i would conduct a test. I sprayed the exterior of the rolled up window with glass cleaner to see where the water would fall on the vapor barrier. What I saw was interesting. Most of the water that falls on the vapor barrier gets dropped into the cavity of the door with a natural "sill" the Holden designers designed into the vapor barrier (this is the front door, not sure about the rear). In this picture you can see where the cleaners starts to hit the barrier and where it pools to drip off into the cavity.

Image Image


Remedies / Fixes

Replace - Well the obvious fix it to beef up or replace the butyl rubber seal at the bottom of the vapor barrier. As I have removed mine and reinstalled it a few times it seems to loose some stickiness each time. You can get a roll of new butyl rubber from various sources. 3M calls it "Window Weld Sealer" and the key things you want to look for is that it is round and not flat like tape. Sizes seem to range from 5/16 to 3/8 of an inch. Bigger the better I say, it will always compress.

Not sure if it would be worth it to remove all the old butyl rubber from the vapor barrier as it would be pretty hard to do and may end up damaging the barrier in the process. I would put it right next to the old stuff in a continuous bead all along the bottom. I would clean off, or at least knock down big glops, of old butyl rubber sticking to the door using lacquer thinner, alcohol or the like to make sure all the micro debris I mention earlier is gone and you have a good surface to stick the new stuff to. Then use a roller of some type to make sure you get a good continuous seal. I got a roller when I did my sound deadening project but I think you can get something like this in the flooring dept at Home Depot:
Image

Drip Rail - Although I have not done this yet I think a good lesson I learned from This Old House would come into play here. That is in order to control drips create a drip rail so when the water comes down the face of material something stops it and it is forced to drip. I would take some of that butyl rope and make a line at the bottom of the vapor barrier just past where it naturally drips. Something like the yellow line here:

Image

Barrier - The other idea I had was to create an inner barrier that rested on the inside of the door cavity and went as high as to get most of the water coming in and down to the bottom of the door cavity to keep water off the main vapor barrier entirely. Seems like that might be a bigger task keeping it out or the way of the glass and regulator assembly. Another idea I found, I think this was a Camaro, had a similar idea where they did not even try to seal up the vapor barrier at the bottom rather just lit it empty in to the door cavity throught a slit in the metal skin:
Image

So here's to hoping none of us have this issue but if you do chime in with how you solved it! Stay dry my friends.

_________________
Steve Walker
Azusa, CA
'11 PPV 9C3 Huron White


Last edited by smwalker on Mon Jul 24, 2017 4:07 am, edited 1 time in total.

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PostPosted: Mon Jul 24, 2017 2:35 am 
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Joined: Mon May 30, 2016 8:12 am
Posts: 252
Location: phx az
the wife had found this after i had told her about our 14 leaking

https://gm.oemdtc.com/1442/floorcarpet- ... rice-ppv/4


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PostPosted: Mon Jul 24, 2017 4:04 am 
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Joined: Mon Jul 29, 2013 6:44 am
Posts: 1148
Location: Azusa,CA
s/c'd cav wrote:
the wife had found this after i had told her about our 14 leaking

https://gm.oemdtc.com/1442/floorcarpet- ... rice-ppv/4



OOh very nice. Start with page one and work your way through all the possibilities.

I still like my drip rail idea, gonna try that.

_________________
Steve Walker
Azusa, CA
'11 PPV 9C3 Huron White


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PostPosted: Mon Jul 24, 2017 5:32 am 
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Joined: Mon May 30, 2016 8:12 am
Posts: 252
Location: phx az
i think mine is something in the door causing it to leak over the top of the sill seal , which is likely the water barrier


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