Rear Quarter Windows Area Interior leak

[MericaMopar]

'64 2 door Newport. I have a leak on both sides in the interior at the bottom area of the rear quarter window panels. Water on the passenger side is coming through at the bottom back corner of that area, and the driver side water is coming from under the middle of the interior panel there.

Should water even be trying to escape the 'vapor barrier' to the inside of the car? Is the plastic sheet designed to be a complete water seal?

Pic is the best one I have of the vapor barrier. The service manual doesn't describe a water leak potential here, so I'm a bit confused.

 

[detmatt]

I think the main function of the plastic sheeting is to keep road dust out of the interior. Maybe it’s coming in around the weather seal at the base of the quarter windows.

 

[MericaMopar]

I think the main function of the plastic sheeting is to keep road dust out of the interior. Maybe it’s coming in around the weather seal at the base of the quarter windows.

The window seal is about gone on one side, I replaced the other side with a DIY solution, but I am going to redo that one with a better solution. But, I would suspect that water that enters the quarter area should drain out through the rocker drains, right? It is a several inch climb from the bottom of the rocker to the nearest opening of the inside sheet metal.

 

[detmatt]

The window seal is about gone on one side, I replaced the other side with a DIY solution, but I am going to redo that one with a better solution. But, I would suspect that water that enters the quarter area should drain out through the rocker drains, right? It is a several inch climb from the bottom of the rocker to the nearest opening of the inside sheet metal.

Agreed I had the same thought but the only other place I can think of you’re not going to like...maybe it’s coming in around the back glass and running down the front of the wheelhouse. How about some pics of the whole car? Have we seen it?

 

[MericaMopar]

Agreed I had the same thought but the only other place I can think of you’re not going to like...maybe it’s coming in around the back glass and running down the front of the wheelhouse. How about some pics of the whole car? Have we seen it?

The back glass used to leak, I have fixed that and verified it does not leak anymore.

This car sat from 1984 to 2020 inside a polebarn where many generations of mice made a nice luxury condo out of it. I am in the process of fixing the interior of it. Patched the floor pans, new headliner, repainting all the trim, dash, cleaning the door panels, new seats, etc. I want to fix any water leaks before I put carpet down. I got it running and driving last fall.

 

[Ross Wooldridge]

The vapour barrier must tuck back into the rocker area at the bottom, otherwise any water that gets on it will simply run down into the passenger area.

I can't tell from your pics if the plastic is properly positioned, but I've seen much evidence in other cars when the plastic has been removed and not replaced - ruined interior panels, with warped and rotten panelboard - and or the plastic has been put back but not tucked into the slots at the bottom, resulting in wet carpets.

 

[MericaMopar]

The vapour barrier must tuck back into the rocker area at the bottom, otherwise any water that gets on it will simply run down into the passenger area.

I can't tell from your pics if the plastic is properly positioned, but I've seen much evidence in other cars when the plastic has been removed and not replaced - ruined interior panels, with warped and rotten panelboard - and or the plastic has been put back but not tucked into the slots at the bottom, resulting in wet carpets.

Ah, ok. Mine must have been removed at some point then and not put back in properly. Each side had the plastic held on with a different type of adhesive, and definitely not tucked back into the rocker area. Thanks, I will probably just replace them with some thick construction vapor barrier plastic and make sure to position them correctly. My driver's door does not have one at all which is probably why the door panel is warped.

 

[Ross Wooldridge]

There you have it. Good luck!

Keep in mind there is various areas of adhesive, just not at the bottom unless there was no place to tuck the plastic in, and then the adhesive generally was positioned in such a way as to promote water to run down towards the slots anyhow.

 

[MericaMopar]

I came home today after the first really good rain of the year to find my new headliner stained on both sides! Hopefully you can see the water stain in the picture.

After I found this, I scraped all the old sealant off of the drip rail and put new sealant in. I hope that's where the source of the water was coming from.

 

[Ross Wooldridge]

Booo, what a drag. Hopefully you can wash that out.