LS430 2001: Water on passenger carpet mystery

[ThePerfectionOfLexus]

Hi guys

I've noticed that the passenger floor carpet gets a bit soaked after a longer period of rain in my pre-facelift.

I've been reading up a lot on this online and have checked almost all possible water drains on the car. The only place I've left behind to check is the rear sunroof drains. However, all the sources online seem to have an outcome of water under the carpet. The strange thing is that, in my case, the bottom of the carpet is completely dry, so the water ends up on top of the carpet only.

While I had the carpet lifted up, I've checked the AC drain, and it's fine. I also checked the cabin filter compartment, as I had a suspicion of water dripping on the carpet, but the compartment is dry (picture attached).

I've attached a picture with a marking showing where the carpet is wet and one with the floor mat. The floor mat is wet at the bottom only and always dry on top.

Do you have any idea what the culprit could be?

Thanks

[Spock66]

1 hour ago, ThePerfectionOfLexus said:

Do you have any idea what the culprit could be?

I'd suggest could be the windscreen.

[ThePerfectionOfLexus]

2 hours ago, Spock66 said:

I'd suggest could be the windscreen.

Thanks, the windscreen doesn’t seem to be wet anywhere on the inside. I’ve tried to find any spots.

It just beats me, how water can end up in the marked area, without any trace at all. Specially the under part of the carpet being totally dry, which usually is soaked in these situations. 

[Razor61]

Could it be the vent on the transmission tunnel spitting out water/moisture?

[Razor61]

1 minute ago, Razor61 said:

Could it be the vent on the transmission tunnel spitting out water/moisture?

Forget that, just re read the original post. The floor mat isn't wet on the top so it can't be that.

[RONNIE W HODGEKINSON]

20 hours ago, ThePerfectionOfLexus said:

Hi guys

I've noticed that the passenger floor carpet gets a bit soaked after a longer period of rain in my pre-facelift.

I've been reading up a lot on this online and have checked almost all possible water drains on the car. The only place I've left behind to check is the rear sunroof drains. However, all the sources online seem to have an outcome of water under the carpet. The strange thing is that, in my case, the bottom of the carpet is completely dry, so the water ends up on top of the carpet only.

While I had the carpet lifted up, I've checked the AC drain, and it's fine. I also checked the cabin filter compartment, as I had a suspicion of water dripping on the carpet, but the compartment is dry (picture attached).

I've attached a picture with a marking showing where the carpet is wet and one with the floor mat. The floor mat is wet at the bottom only and always dry on top.

Do you have any idea what the culprit could be?

Thanks

Its Most LIKELY to be CONDENSATION coming from your Windscreen   I get it too  Common situation in these cars

[Malc1]

In my 1991 Ls400 in Wales last week my sun hat sitting on the back seat got a bit wet overnight .....  just sitting there ...  all windows fully closed etc BUT it got wet a little .......  I think the incredibly torrential rain must have found an impossible weak spot and let some in, maybe overrode the usual grommits and window rubber seals whatever  ......  nowhere else in the car ....  of course 

That torrential rain might, for you, have just penetrated the impossible

Malc

[ThePerfectionOfLexus]

7 hours ago, RONNIE W HODGEKINSON said:

Its Most LIKELY to be CONDENSATION coming from your Windscreen   I get it too  Common situation in these cars

Thanks Ronnie, but it seems to be a bit more than condensation though. It’s not soaked, but very wet.

[ThePerfectionOfLexus]

3 hours ago, Malc1 said:

In my 1991 Ls400 in Wales last week my sun hat sitting on the back seat got a bit wet overnight .....  just sitting there ...  all windows fully closed etc BUT it got wet a little .......  I think the incredibly torrential rain must have found an impossible weak spot and let some in, maybe overrode the usual grommits and window rubber seals whatever  ......  nowhere else in the car ....  of course 

That torrential rain might, for you, have just penetrated the impossible

Malc

Thanks Malc. You might be right, but I’m having a hard time finding the source. The wet spot is in a very unusual location.

[Neilo]

Wonder if the AC condensation tube is connected properly AC side, although you checked this ...does the carpet stay dry with the AC turned off?

The carpet must be rubber backed then?

No traces of damp coming down from the surrounding carpet?

I'd let it dry out then put the force of water from a hosepipe on the exterior passenger door window / windscreen & cowling / sunroof (last) wait at least 10 minutes between each location, check the carpet each time...this should tell you if rain is getting in or not.

On my Subaru I had a similar problem - found a build up of silt underneath the wiper cowling, this was stopping water from running away down the correct channels beneath it, water found its way down into the blower fan and came in from under the dash...probably not possible on a Lexus but I don't know.

Cheers & best wishes. 

 

 

   

 

[ThePerfectionOfLexus]

On 10/27/2023 at 10:33 AM, Neilo said:

Wonder if the AC condensation tube is connected properly AC side, although you checked this ...does the carpet stay dry with the AC turned off?

The carpet must be rubber backed then?

No traces of damp coming down from the surrounding carpet?

I'd let it dry out then put the force of water from a hosepipe on the exterior passenger door window / windscreen & cowling / sunroof (last) wait at least 10 minutes between each location, check the carpet each time...this should tell you if rain is getting in or not.

On my Subaru I had a similar problem - found a build up of silt underneath the wiper cowling, this was stopping water from running away down the correct channels beneath it, water found its way down into the blower fan and came in from under the dash...probably not possible on a Lexus but I don't know.

Cheers & best wishes. 

 

 

   

 

Well I’ve been monitoring the situation for a month now with the floor mat removed for clarity. We have had lots of rain and the AC has been on all the time.
The carpet stayed fully dry all the time. So it seems to be correct what Ronnie said about condensation. 
Condensation seems to collect under the rubber floor mat, but when the floor mat is removed there is nothing to spot.

[Neilo]

29 minutes ago, ThePerfectionOfLexus said:

Well I’ve been monitoring the situation for a month now with the floor mat removed for clarity. We have had lots of rain and the A/C has been on all the time.
The carpet stayed fully dry all the time. So it seems to be correct what Ronnie said about condensation. 
Condensation seems to collect under the rubber floor mat, but when the floor mat is removed there is nothing to spot.

Pleased that it is staying dry for you under those circumstances at least.      

 

[Neilo]

Just a thought to protect the carpet if it is condensation - puppy trainer mats are very thin and easily cut to size, one placed under your floor mat would be unnoticable and soak up any water effectively.    

[Boomer54]

20 minutes ago, Neilo said:

Just a thought to protect the carpet if it is condensation - puppy trainer mats are very thin and easily cut to size, one placed under your floor mat would be unnoticable and soak up any water effectively.    

There's a joke in there somewhere dying to get out.

Just a first try "If you buy a dog (sic) get a mat".

[John N]

Just looking at the picture where you have circled. That is the spot where the wire from the O2 sensor on the exhaust comes through the floor. Check underneath, the rubber grommet may have come out.

It had on mine. or someone may have fitted an 'after market' O2 sensor without a grommet.

John N