CUTiger80

I have been chasing this water leak for some time now. The car is my daughter's and she has it away at school. Finally traded cars with her so I could spend an extensive amount of time chasing this down.
I have removed most of the trim around the door threshold so that I can prop the carpet up away from the metal floor to dry it and to see what is going on.
I thought it was related to the moon roof. Checked all 4 drains and they are working fine. Sprayed a heck of a lot of water on the roof last night, around the moon roof, and at the seam above the doors. There was no water on the floor under the carpet. Got about 1/4" rain overnight and checked this morning. Again, no water on the floor under the carpet. I placed a washcloth on each floor board right on top of the drain plug so that it would be easier to tell if there was any water getting in.
Drove the car into work (20 mi.) with no rain and only slightly damp roads. I ran the A/C full-time to dry to finish drying the carpet out. When I got to work all 4 floors had some standing water and all of the washcloths were soaked.
I had put some rags where the "B" pillar meets the floor on both sides because my daughter had said that she had noticed the seat belts were sometimes damp. Both of these rags were wet as well.
I have checked around the hatch and where the spare tire is and all of this area is bone dry.
Any idea of where this water may be coming from?
Any ideas on what to check next?

NateJG

You mentioned running the A/C; but didn't mention that the A/C was draining outside of the car (Damp seatbelts would seem to eliminate the A/C as a culprit, I admit - but then again - your checklist is already pretty long.).

thomas1

I would check drain hose on AC condenser....But are you sure the drains on sunroof are not broken between sunroof and exits....I remember somebody having that issue....

CUTiger80

NateJG,
I did not check that this morning. Do you know where the drain tube is located?
I did check the seatbelts and they are slightly damp, but not wet.
If it were to be the A/C condensate drain, is it reasonable that it could get wet in all 4 floorboards?

CUTiger80

thomas1,
First, thanks for your reply. This has really been a frustrating problem.
Do you know where the drain tube for the A/C should be? If it is clogged, it is reasonable that I could get water in all 4 floorboards?
As far as the moon roof drains, I did pour about 1 pint of water through each one last night and they all seemed to flow fine. I guess the lines could be broken or split somewhere, but I would think that I would see the water inside the car right after I tested the drains if this were the case.
The drains for the rear of the moon roof were difficult to verify. I ended up having to pour the water into the aluminum channel that runs along each side of the moon roof because I couldn't get access to the location where the drains actually exit the channel (like you can on the front corners).
It would seem that the only way to truly verify this is to pull down the headliner which seems like a bear. I did pull down the headliner at the very rear and felt up inside of it as far as I could reach and determined that it was dry. I could see the rear drain tubes using a flashlight, but could not reach them.

rxpx40

iTrader: (1)

This is really reaching, but for your AC condensate drain, pull the in-cabin air filter and see if you can tell what is going on in there. It's behind the glove box. If it is soaking wet, there's a good chance the drain tube is clogged. How it's getting to all floorboards is a puzzle, I admit.

CUTiger80

rxpx40,
Thanks for the reply. I will check the filter. I also think that I will drive it home this evening without the A/C on to see what I get.
The other odd thing is that I had a small rag rolled up and stuffed down next to the right rear door seal (where the lighted Lexus logo would have been if I had not pulled off that piece of trim) and it was wet. That portion of the body is "higher" than the floor, which leads me to believe that the water would have either had to come down the "B" pillar or run along the raised threshold area somehow.
Puzzling.

thomas1

Yea that makes me think the line or lines are broken between the sunroof and exits. I know the front ones are behind the kick panels on both sides of the car.

CUTiger80

I gathered a little more information last night and this morning.
Last night I checked the cabin filter behind the glove box and it is bone dry.
I placed a small washcloth in all 4 floorboards. I also stuffed a small towel up in the molding where the "C" pillar meets the floor on both sides. I removed the plastic trim around the bottom of the passenger side "B" pillar and stuffed a rag where it meets the floor.
I left the car parked slightly uphill last night and we got over 2" of rain; that intense pouring down scary stuff we get in the South this time of the year.
I came out this morning to find about 8-10 ounces of water standing in the rear driver's side floorboard. The towel that I had stuffed up in the bottom of the "C" pillar was also soaked. The other 3 floorboards and towels were all dry, including those that I had stuffed at the bottom of each "B" pillar. I dried out the water and then placed a large folded beach towel between the carpet and metal floor on the rear driver's side and drove to work with the A/C on wide-open (temp as low as it would go and fan as high as it would go).
When I got to work (20 miles or so) I found standing water in all 4 floor areas. The beach towel was totally saturated. Both of the towels that were stuffed at the bottom of the "C" pillars were soaked. The carpet around the bottom of the driver's side "C" pillar was also soaked. If I had to guess, I would estimate that I sopped over a gallon of water out of the car. I opened the hatch and pulled down the headliner at the rear and the top seemed dry. I checked the A/C condensate drain and I saw several drips come out of it, but the engine was off and had been for 5 minutes or so.
The leak is not related to the heater coil (as others have suggested) because the water inside the car does not have anti-freeze in it. I doubt that it is totally related to the A/C condensate drain, but that may be contributing. I still have to rule that out.
My plan is to remove the back seat and the trim around the base of each "C" pillar to see if I can determine what is going on.
I would also like to remove the headliner, but I am afraid that job (and the replacement of the headliner) is too big for me. Has anyone done this before and can verify whether it is as bad as it looks?
I also want to try and seal up the moon roof from the top (possibly with duct or painter's tape) and spray water on the roof to see if it is related to the moon roof drains or something else (like a leak in one of the body seams).
Any other suggestions (other than taking it to the dealer or selling it) would be appreciated.

NateJG

Has the windshield been replaced?

I have a horror story about one that was installed so poorly (mis-registered sealant) that wind came in from underneath it - the symptom was noise - but you apparently have such a huge leak that something really strange has happened.

Has the car been in an accident requiring body modifications (like a front fender - leaving a crack or hole at a pillar)?

CUTiger80

NateJG,
I don't know if the windshield has been replaced. We have only had the car for 2 years and it has not been replaced since we've owned it.
There is a misalignment between the bumper guard and the left rear quarter panel that is only slightly noticeable and was that way when we bought it. The AutoCheck (like CarFax) report that I did before buying the vehicle stated that there was a minor accident back in 2005 involving the left rear.
My plan at this point is to pour a lot of water in the moon roof channels (one side at a time) to try and determine if the rear drain tubes are leaking. (They are not stopped up because water comes out behind the rear wheels on each side when I pour water into the channel on that respective side.) I really doubt this is the culprit because that would mean (during the heavy rain night-before-last) that enough water would have had to leak by the moon roof seal (which looks good, by the way) to produce over a gallon of water inside of the car.
Depending on the outcome of that test, my next approach is to seal off the moon roof entirely with poly and duct tape and then start to pour water onto various areas of the roof to see if I can isolate where it is coming in. The carpet is definitely wet at the base of each "C" pillar so I suspect it is near the back somewhere, possibly where the roof rack attaches to the roof.
Like I have stated before, I really think that I could shorten this process by removing the headliner, but I'm afraid that I either can't get it down without damaging it, or won't be able to secure it back in place when I'm finished. I think that all I need to do is pull down the rear 1/3 of it to be able to see what is going on.
Do you or anyone else know of a post that describes how to remove the headliner and re-install?

NateJG

Stop by one of the Paintless Dent Repair shops - they're pretty good ( in my experience - had dozens of hail dents removed on my last car ) at removing and replacing the headliners to fix dents. Perhaps one would either do it for you, or share the technology.

Tagging onto your observation, is the water dirty or clean? Is it more severe in an area? The accident repair area is ripe for further investigation - if the water comes in primarily when the car is moving.

I've chased water leaks around a camper trailer I owned years ago - to find that water was coming in a crack in the putty sealant that was barely wide enough to pass a cigarette paper (don't ask).

NVAKeith

iTrader: (1)

Just had a thought reading the recent thread on installing new tail lights...check the seals on yours. It appears water from the roof channels drains around the hatch opening and around the tail lights. Here is the thread on how to remove them:

https://www.clublexus.com/forums/rx-second-generation/787108-install-eagle-eye-after-market-tail-lights.html

If your RX had bodywork on the rear, they likely removed the lights during the repair.

CUTiger80

NVAKeith,
You may be onto something based on what I observed/tried this weekend. I didn't have much time because of other commitments, but this is what I did do.
On Friday evening I think that I eliminated the rear moon roof/roof drains. I poured 2L of water into each side channel and I got exactly 2L of water out at the drains behind the rear tires.
On Saturday morning, I removed the left rear seat and pulled the carpet back under it so that I could expose the metal floor pan under the carpet. This is the first place it seems that the water gets in and then spreads throughout the car.
Yesterday, I sprayed water all over the windshield and the front cowling to try and eliminate the windshield, its seal and the front drains. I got no water in the car. I then progressed little-by-little further back, focusing primarily on the left side where I had removed the seat. I sprayed water on the top and side of the car for probably an hour (off and on) and did not notice a single drop of water in the car. Based on previous experience that my daughter and I both had in the car getting wet but not noticing water in the car until it was driven, I decided to drive the car around the block right before dark. When I slammed on brakes I heard a distinct "swooshing" sound of water flowing. I immediately stopped and the area under the left rear seat was very wet. The water had flowed out of the trunk area from a space that appeared to be below the trays that hold all of the jacks, etc. I also had water on the rear passenger side right beside the "C" pillar. I had stuffed towels in both locations to prevent any water from spreading.
My next step (it will be later in the week before I have a chance to work on it again) will be to remove all of the flooring in the rear and the plastic trays to see if I can tell where the water is actually coming in.
Based on your suggestion, I first may try saturating the area around the left taillight to see if this is indeed the culprit. I will certainly report back what I find. I feel like I'm getting close to solving this puzzle.
Thanks to all of you for help and for reading thought my rather lengthy explanations. I'm an engineer and I am programmed to solve problems methodically and logically. (My wife thinks I'm an alien when I get into this mode. I guess methodic and logic doesn't apply to baking a cake.)

CUTiger80

Update.
This is what I found over the weekend.
I pulled out all of the access doors and plastic trim in the rear cargo floor area, all the way down to the sheet metal. I sprayed water all around the left and right rear areas, concentrating on the hatch and tail light areas. I was able to determine that it was leaking around the left rear. I continued to narrow this down until I could determine that it is leaking around the seal between the left tail light assembly and the body. I pulled out the tail light assembly and visually inspected the gasket. It does not appear to be torn or rolled or crushed, but it seems that this is the only place where water can come in that area. I've decided to go ahead and replace it, but I can't seem to find one on the internet at any of the parts places. Does anyone know if this is one of those "dealer-only" parts? Thanks again for all of your help in getting to this point. I will continue to update this post as I (hopefully) finally solve this problem.