Wet under drivers side mat.
Carpet wet? 
First you must isolate where the water is coming from. Pull back the carpet.
Is it only Passenger side, Driver side, Roof?
Problems:
1. The rubber molding is not seated correctly
+ Check the rubber around the door as well as around the door jams
2. Evaporator is leaking (A/C)
+ Could be costly (about $650 from a regular mechanic)
+ Most likely only the passenger side will be wet
+ AC will be blowing warm
+ Distinct smell from the liquid leaking out
3. Hose Leaving Evaporator box is leaking into the car or is clogged
+When you look in the engine bay you will see a black rubber hose coming out from the fire wall. This is where you can have a clog.
4. Rubber Gromets under the carpet is missing or leaking
+ When you remove the carpet you will see the 2 black rubber gromets.
+ Check to make sure they are snug in place, if not place some silicon around it.
+ Sometimes the gromet drops out (can also cause a whistling noise when you accelerate)
5.Moonroof Drain Clogged
+ Fill a cup of water and place it in the Moonroom Drain
+ It should flow out underneath behind the front tire.
+ Check if it is leaking in the car.
+ If it is use compressed air to blow the debri out of the drain.
+ Video: http://www.youtube.com/watch?v=5-JE2Isu0qs
First you must isolate where the water is coming from. Pull back the carpet.
Is it only Passenger side, Driver side, Roof?
Problems:
1. The rubber molding is not seated correctly
+ Check the rubber around the door as well as around the door jams
2. Evaporator is leaking (A/C)
+ Could be costly (about $650 from a regular mechanic)
+ Most likely only the passenger side will be wet
+ AC will be blowing warm
+ Distinct smell from the liquid leaking out
3. Hose Leaving Evaporator box is leaking into the car or is clogged
+When you look in the engine bay you will see a black rubber hose coming out from the fire wall. This is where you can have a clog.
4. Rubber Gromets under the carpet is missing or leaking
+ When you remove the carpet you will see the 2 black rubber gromets.
+ Check to make sure they are snug in place, if not place some silicon around it.
+ Sometimes the gromet drops out (can also cause a whistling noise when you accelerate)
5.Moonroof Drain Clogged
+ Fill a cup of water and place it in the Moonroom Drain
+ It should flow out underneath behind the front tire.
+ Check if it is leaking in the car.
+ If it is use compressed air to blow the debri out of the drain.
+ Video: http://www.youtube.com/watch?v=5-JE2Isu0qs
Pole Position
Joined: Feb 2002
Posts: 3,124
Likes: 40
From: California
I too have this problem and never could figure it out where it was coming from.
It appears to be fresh water, I will have to further research the key point locations to see where the water is actually coming from.
Thanks for the research and write up Chico! Very valuable information.
It appears to be fresh water, I will have to further research the key point locations to see where the water is actually coming from.
Thanks for the research and write up Chico! Very valuable information.
Rookie
Joined: May 2007
Posts: 73
Likes: 0
From: FL
I have fixed a few of my customer cars and it usually seems to be the seal for the middle of the EVAP case. It drips on the driver side because it follows the contour of the trans tunnel. The best way to check is to pull the carpet up on the passenger side(its easier on the PS) and look with a light at the bottom of the case and find the screws that hold it together. If they are rusty then you have a water leak. I will tell you that the case is 2000$ and to repair them is labor intensive and can end in terrible results if it isn't done correctly. Hope it helps,
Allen
Allen
Lexus Champion
Joined: Feb 2002
Posts: 4,466
Likes: 14
From: Cali
I have fixed a few of my customer cars and it usually seems to be the seal for the middle of the EVAP case. It drips on the driver side because it follows the contour of the trans tunnel. The best way to check is to pull the carpet up on the passenger side(its easier on the PS) and look with a light at the bottom of the case and find the screws that hold it together. If they are rusty then you have a water leak. I will tell you that the case is 2000$ and to repair them is labor intensive and can end in terrible results if it isn't done correctly. Hope it helps,
Allen
Allen
I now know this isn't the case; I got the carpet all dried out and the dampness reappeared a while later. I don't drive the car too much and I haven't actually washed the car since late May (detail spray is my friend)... and the car doesn't go out in the rain (not that we get much here anyway).
Also, the water is nice and clean & clear, definitely not outside water.
So the Evap is up under the passenger side of the dash? I've never really noticed it (installed a Pioneer Navi unit a year ago, didn't see the Evap, but wasn't looking for it). Does this require complete dash removal?
If so, I'm selling the damn car!
Instructor
Joined: Feb 2002
Posts: 793
Likes: 63
From: California
The Evap on a ls400 and sc is behind the glove box. It should be the same for the GS. You have to remove the bottom panel of the dash. And remove the glove box and you should be able to access it. Doesn't take alot of brains to remove it, just time. Take pics during the removal so you remember where everything goes back.
Thanks for the heads-up Allen. I've recently noticed the dampness as well (on the driver's side) and when I pulled up the carpet there was 1/4" of water down there. At first I suspected that it was related to the sunroof drain (my car was totally repainted a year ago, maybe some crap got in there) or was related to the new windshield (also installed after new paint).
I now know this isn't the case; I got the carpet all dried out and the dampness reappeared a while later. I don't drive the car too much and I haven't actually washed the car since late May (detail spray is my friend)... and the car doesn't go out in the rain (not that we get much here anyway).
Also, the water is nice and clean & clear, definitely not outside water.
So the Evap is up under the passenger side of the dash? I've never really noticed it (installed a Pioneer Navi unit a year ago, didn't see the Evap, but wasn't looking for it). Does this require complete dash removal?
If so, I'm selling the damn car!
I now know this isn't the case; I got the carpet all dried out and the dampness reappeared a while later. I don't drive the car too much and I haven't actually washed the car since late May (detail spray is my friend)... and the car doesn't go out in the rain (not that we get much here anyway).
Also, the water is nice and clean & clear, definitely not outside water.
So the Evap is up under the passenger side of the dash? I've never really noticed it (installed a Pioneer Navi unit a year ago, didn't see the Evap, but wasn't looking for it). Does this require complete dash removal?
If so, I'm selling the damn car!
I have the same problem. I checked the carpet on the drivers side and it was soaked. I pulled back the carpet and found the leak. The water is dropping where the red circle is on the picture and running down to the floor. My drain hose behind the firewall seems to have a steady flow of water, but I'm not sure if it's obstructed or not though. The dark stuff is some type of undercoating.
Lexus Champion
Joined: Aug 2006
Posts: 2,857
Likes: 0
From: ~626~ S.G.V
I told you guys not to let girls sit on the driver seat!!! =)
I have the same problem too. I just put a towel there....and that was a bad mistake...it started to smell like a$$ after a while..so i just left it.
I have the same problem too. I just put a towel there....and that was a bad mistake...it started to smell like a$$ after a while..so i just left it.
its could be a leaking Evap Case cause its has a rubber seal and with the age of our GS the seal could not work over time. i recently just fixed mine at home. the crappy thing with the GS and only the GS in the lexus family of cars you have to take the dash out to fix that leak with the other lexus you only have to take out the glovebox. it took me about 6 hours with a 20 year master lexus tech helping me. i just resealed it and put it back together. Its a 5 dollar fix if your evap isn't bad. Also mine did leak on the driver side and it went all the way to the back seat
Pole Position
Joined: Jun 2006
Posts: 313
Likes: 7
From: Georgia
It seems like the only time mine gets really wet is when it rains outside. I notice after it sits up a while in the rain, it has a bunch of water on the floor. Its really frustrating and I hope it doesnt cost an arm and a leg to fix....... Anyone else solve this problem where it didnt turn out to be the evaporator?
The last thing I want to do is pull a dash and have to worry about dash rattles.
The last thing I want to do is pull a dash and have to worry about dash rattles.
Pole Position
Joined: Jun 2006
Posts: 313
Likes: 7
From: Georgia
I had the same thing. It seems like a ton of people has or had this problem. I believe if its your evap then you will be leaking anti freeze. You can smell antifreeze for sure. If it just water, then you may have a clogged AC drain tube. Try unclogging the tube from under the car and see if that helps! You can try blowing air into the tube to maybe some wire? That was my problem, thank goodness it wasn't the evap.
well it has happened to me too. my passenger front and rear were wet. this is the first time i noticed it so im not sure where it might be coming from. it was clean water. so i just have no clue. Anyone got anymore ideas