Floor won't dry out!

I have a 93 Grand Am with a constantly wet floor. About 3 weeks ago I vacumed all the water that I could out. It was wet on both sides, front and rear. No windows have ever been left open, so I am at a loss as to how the water is getting in. I've also confirmed that it is not antifreeze. I've kept the car garaged as much as possible and it has not been rained or snowed on the last 3 weeks. Now the passenger side as well as both sides in back feel a little damp, but not soaking wet like before. However, the drivers side is still very wet. I've vacumed it a couple more times in the last few days only to find the carpet soaking the next day. Anyone have any ideas?

which side is it wet on? driver? passenger?

You might have a busted Heater Core.
Leave the AC off untill you know for sure.

which side is it wet on? driver? passenger?

You might have a busted Heater Core.
Leave the AC off untill you know for sure.You might want to read the entire post

Have 95 Grand Am both sides wet, firewall on both sides rusted out very small holes. The water didn't show up until the pads under the carpet became soaked for both front and back. Had to remove carpet (seats) to let dry out. Did drill a few small holes in the floor front and back to let future water drain out. Did repair the rusted metal with heavy spray of undercoating.

Got two for you on this one:

Check the heater core, it's under the center console / dash area first. If that is not it...

Did you have ANY work done under the dash lately? Particularly cooling system?

The bottom of the dash on this car (I have one) is a giant tray that guides condensation from the a/c system to small port near the center and out the bottom of the car. It's possible this hole is plugged, but in my case, I had the heater core replaced at a shop and the water problem started. I checked it out myself (good help is SO hard to get) and found the dips*()ts had BROKEN off some of the tray because they were too lazy to get out all the bolts.

I removed the whole assembly and glued it, and then used a woodburning iron to gently "melt" the entire length of the broken seams, and reinstalled it myself VERY CAREFULLY. I have not had a problem with it for 4 years.

It may be possible to break this tray in an accident, or on a very hard bump, if someone kicked it hard enough, as it is exposed down there a bit...but not easily.

I left this in another post on here, but it will help you. If you're going to get in there and do it, you might as well take care of everythig at the same time.

Remove the wipers and the black plastic shield to expose the damper on the passenger side. Pull it out and get a new gasket for it as the original gasket was a thin foam. The replacements are much thicker. If your old one is ok, clean everything up and put the old one back in and silicone the crap out of it, just make sure the silicone does not obstruct the damper door.

Next, while you still have the plastic cover off, check your drain holes on the passenger and driver side. The car rusts badly in both spots because of the moisture that flows down there. It will often pool if the drains become blocked with leaves, etc. On the driver side, you should remove the wiper motor as you will find there is a rust hole at the drain behind it. I went to the local Napa and bought some body seam caulk which hardens like plastic. Smear it on with rubber gloves. You may also want to caulk around both electrical blocks (the one for the computer and the one on the drivers side for the instrument cluster) They are located each side by the hood hinges. I actually used the window sealing caulk which comes in a roll that you can roll like playdough. Pack it around the blocks and it hardens in a few days and is water tight. On the interior under the dash, pull your firewall matting off the firewall. I cut mine down the center on each side to get it out and I was able to put it back in fairlly easy when I was finished. Behind the foam matting on the drivers side, look way up on the firewall above the steering column (with a light) and you will likely see where water is coming in from where the drain has rusted on the drivers side. If it is not too bad, caulk it well. It is hard to reach, but if you don't seal it, you will still get leaks. Also check the seam that runs horizontally all across the firewall. It is very prone to leaking especially on the passenger side. Next, pull back the carpet on both the drivers side and passenger side to check for rust. I found mine was starting to rust out on the passenger side. When water sprays up under the car, it is directed right against the floor board through a hole in the control arm. After a while it just washes through. I used roofing tar to seal my floor as it was not too bad, but I sealed it well. By the way, my car is in really good shape and has been rustproofed every year since new. Just bad design, caused a few leaks. Also, if you have had water coming in on the passenger side by the damper, check the electical connection that is mounted to the firewall under the glove box. Water will run right into it and cause it to corrode. In my case , it caused high idle in wet weather. I pulled the connection apart, cleaned it with WD40 and put it back together and never had the problem since. Also pull your connection out of the computer to make sure it is not green. If it is, you know water has been leaking onto your computer as well.

I left this in another post on here, but it will help you. If you're going to get in there and do it, you might as well take care of everythig at the same time.

Remove the wipers and the black plastic shield to expose the damper on the passenger side. Pull it out and get a new gasket for it as the original gasket was a thin foam. The replacements are much thicker. If your old one is ok, clean everything up and put the old one back in and silicone the crap out of it, just make sure the silicone does not obstruct the damper door.

Next, while you still have the plastic cover off, check your drain holes on the passenger and driver side. The car rusts badly in both spots because of the moisture that flows down there. It will often pool if the drains become blocked with leaves, etc. On the driver side, you should remove the wiper motor as you will find there is a rust hole at the drain behind it. I went to the local Napa and bought some body seam caulk which hardens like plastic. Smear it on with rubber gloves. You may also want to caulk around both electrical blocks (the one for the computer and the one on the drivers side for the instrument cluster) They are located each side by the hood hinges. I actually used the window sealing caulk which comes in a roll that you can roll like playdough. Pack it around the blocks and it hardens in a few days and is water tight. On the interior under the dash, pull your firewall matting off the firewall. I cut mine down the center on each side to get it out and I was able to put it back in fairlly easy when I was finished. Behind the foam matting on the drivers side, look way up on the firewall above the steering column (with a light) and you will likely see where water is coming in from where the drain has rusted on the drivers side. If it is not too bad, caulk it well. It is hard to reach, but if you don't seal it, you will still get leaks. Also check the seam that runs horizontally all across the firewall. It is very prone to leaking especially on the passenger side. Next, pull back the carpet on both the drivers side and passenger side to check for rust. I found mine was starting to rust out on the passenger side. When water sprays up under the car, it is directed right against the floor board through a hole in the control arm. After a while it just washes through. I used roofing tar to seal my floor as it was not too bad, but I sealed it well. By the way, my car is in really good shape and has been rustproofed every year since new. Just bad design, caused a few leaks. Also, if you have had water coming in on the passenger side by the damper, check the electical connection that is mounted to the firewall under the glove box. Water will run right into it and cause it to corrode. In my case , it caused high idle in wet weather. I pulled the connection apart, cleaned it with WD40 and put it back together and never had the problem since. Also pull your connection out of the computer to make sure it is not green. If it is, you know water has been leaking onto your computer as well.



This was really helpful to me. I did everything you said, But the leak on the driver side is to high in between the dash and the wall for me to get.. So I'm thinking I'm going to start to rip apart my dash to get to this leak. I am mechanical, but have never done this before... Is there somewhere i can find a manual as to where to begin to start taring this apart?