I still have to find my leak and fix it, between all of the rain, then cold weather we have had, I have not been able to take my seats, and carpet out.
Eventually I'll get around to it.

Right now I am tempted to just buy a 2004 Black Park Ave SC for 7,000.00 and just park this one till I actually have time, to fix a lot of the little things that it needs fixed.
Appreciate you asking though Karl!

Is there a sun roof in your car? If not the trunk lid most likely place for a leak but I think you replaced that seal.
I ran across a car that had a few PDR holes drilled in it to fix some door dings in the truck lid area and that hole let the water run in to the spare tire area.
You might look to see if there is any plastic plugs in any area that'* what the PDR guys
use once they fix the door ding.
It could have been done before you owned the car.
When your ready for a head liner I am sure we can find you one there is more yards here then you can count.

No sunroof, and yeah I replaced the seal, even used some marine grade sikaflex on it, still somehow I get some water that pools up inside the black plastic area surrounding the brake light bulbs, I'm going to seal an are that I suspect, and see how it goes.
I got the car at 27k miles, bought if from my Moms husbands Mother, and I know the full history of the car, never been in an accident, well other than my right before I bought it, my sister backed it out of the garage it was kept in, and lightly scraped the front side.
And once I had a deer jump into my passenger side headlight..

I checked the front floorboards, and they are getting wet also, not sure if from when I am driving, maybe it sloshes back and forth, or maybe a front door is leaking somehow, that or the wiper cowl area..

From what you said about the front I would say your windshield needs to be resealed it don't take much of a area to cause a leak.
It will run down the windshield then leak at the fire wall and run to the bottom in to the floor
Of course best way is to have a pro do it so the windshield is not broken.I don't think the cost is much.
Average price here is like $50 dollars.

As far as your taillights I have seen the RED part pull away from the back.

Pull out the tail light assembly and run some silicone around were the back of the red meets the back of the housing

It could be only one spot to locate it here is a way I have done take the assembly off take the bulbs out fill it up with water were the bulbs go in and watch were water leaks out.

Then blow it dry first with compressed air then reseal it.

I hope this helps some.

It could be thew windshield, I was able to pull the carpet back and I could see it was wet on both front sides, one thing I noticed though is the middle/hump part looked like it had water run down it, maybe that is where it found a way through the firewall.
I have also noticed a little wetness around the kick-plate area under the door, but I don't really think it is coming through there.
If I can get my seats removed, and my carpet, then I can host it down and hopefully find any/all leaks.

There is one area on my brake light assembly where the red lens part seems to have a small gap between it, and the chrome housing, I plan to seal it, and get some rubber washers for the brake light housing bolts/nuts, it had a paper like sealant on them before, and when I last removed it all I had to use was silicone.

Oh yeah, the weird thing is the actual housing does not seem to take in any water, just the black plastic part that covers the actual bulbs, I posted some pics of that a while back.
Pics should be here.
https://www.gmforum.com/buick-172/tr...4/#post1616336

I would say that I am about 95 % sure its leaking at the bottom of the windshield.
And its running down the firewall under the carpet and the back is getting the water transferred by just going and stopping the car and it puddles up in the back.

I would not try to reseal the windshield at the bottom it really needs to be pulled out to dry up any trapped water under the windshield then resealed by a pro.

These guys will do it anywhere in about 30 mins.

I do notice a lot of condensation builds up on the inside of the windshield, but it occasionally gets on the rear one as well, possibly from natural condensation occurring from the water in the floorboards.

If you suspect any front windshield leak, you would think you could feel water on one side of carpet or the other. A flashlight under the dash in rain, can sometimes show water droplets....
Pulling back the carpets, often will give you the best whole picture though!

I have to dry the inside windshield a lot, but it is from condensation, I have pulled the front carpet back a bit, and it looks like water comes in from around the center of the car, around the center hump, but I'll have to look at it while it is pouring down to see for sure..