RX400H Water ingress

[jonathanca14]

Hi Everyone,

I'm after a little advice, first time Lexus owner on a 2006 RX400H

Have owned for a little over two months now and all was going well (Done around 1000 miles in it so far) until car decided to die reversing up onto a steepish drive at a friends house.
Had Check VSC and Hybrid System error and no local garage would touch it so went to Lexus. Turned out to be water ingress into the rear which is well documented here. They drained it out and cleared the codes and now is all OK apart from the fact I still need to try and seal the leaks! I have replaced the rear gas struts with new genuine lexus struts including new feat with good gaskets and used black toyota sealant underneath them, so they are water tight. I also used thread seal on the bolts. I have also resealed the Roofbar bolts and put some black sealant in appropriate areas there. I have also sealed the rear light although this did not appear to be leaking I know its not now!

I have also sealed along the rear seam along the back of the boot.

Since all my sealing its better but im still getting a fast paced drip when I test in photo one at the end of the black sealant where i've put a little clear temporarily just to show in this photo

I know I can seal that last corner, but my concern is there is a big void behind there that water is clearly getting into and if I seal where will it go!

 I also note that the plastic that goes between the rear light and bumper and rubber seal doesnt sit flush at the top, and there is a largish gap at the bottom between it and the bumper. Is this normal?!

 

Thanks for any help given!! 

[Lager shandy]

You could try sealing of the boot to cabin area with sheet plastic and duct tape remove the rear inner panels and bumper etc put a small smoke machine in the boot and you should find your culprit .

[jonathanca14]

haha I mean hiring a smoke machine would still be considerably cheaper than what Lexus wanted to charge just to remove the rear interior - let alone actually find the leak and re fit after! 

 

 

[plastic orange]

This issue seems endemic on these models and very disappointing for a quality car. Drilling a few strategic holes does wonders though.

 

Pete

[jonathanca14]

I was considering a bilge pump there was that much water coming in Sunday!! Better today but it hasn't rained 😐

I'm hoping I have cured the leak which shows around the boot motor, but I'm taking the bumper off Wednesday to try and fix the rear bumper area low level leak. I'm going to follow the standard advice of sealing every single hole I can find!! If I do find anything different from what I've seen on here ill report back.

[jonathanca14]

Small update, managed to get the bumper off today, only bit that was wet was the seal around the vent, so removed and sealed up 

 

I decided to do the bumper brackets as well for good measure, no sign of leaking but pumped full of sealant just in case! 

 

, 

Looking at it logically the hole that has probably caused a lot of the issues is the one in the below photo that has the trim clip and screw in. I'm hoping its been sealed up enough to stop any water coming through it, but if it does ill probably follow what others have done and just seal it up completely as I don't think the trim clip and screw do much!! I also sealed the rubber bungs on the sides just in case, the lower left one was slightly damp...

 

I haven't water tested it yet as I want to give the sealer a good chance to go off! so fingers crossed for tomorrow  !!

[plastic orange]

When I took the bumper off to do a similar job, the car looked like new once it was off with no signs of poor seams etc. I did tiger seal over all of them though just in case, but still got water in. My long term solution was to drill holes, leave bungs out and make a dam so water couldn't travel forward. I only had a problem when I started travelling to our daughter's new house In Banchory and used the very hilly Cairn O' Mount road - basically the dam burst lol. I can't see me keeping the car much longer (had it 5 years), and wouldn't buy another, but don't know what to get yet.

 

Pete

[jonathanca14]

I had the same thought about building a dam!!

 

Small update after checking again yesterday there was still a very slight leak which I thought was coming from the small hole on the pumper with a screw in it previously mentioned in the forum. I decided to remove it completely and filled it with petro putty with a thin layer of black sealant on top. I gave it 24 hours but sadly today the same small weep was still there. I'm fairly hopeful that I've traced it to the bottom clip on the plastic trim next to the rear light. It looks like a normal trim clip that you'd use internally and wasn't sealed in any way, and as water is forces right over the top of it i'm hoping that's the winner, but another 24 hour wait for the sealant to full cure before I re test!! failing this, I might be moving onto drilling holes!! 🙄

[jonathanca14]

On 3/13/2020 at 4:14 PM, jonathanca14 said:

I had the same thought about building a dam!!

 

Small update after checking again yesterday there was still a very slight leak which I thought was coming from the small hole on the pumper with a screw in it previously mentioned in the forum. I decided to remove it completely and filled it with petro putty with a thin layer of black sealant on top. I gave it 24 hours but sadly today the same small weep was still there. I'm fairly hopeful that I've traced it to the bottom clip on the plastic trim next to the rear light. It looks like a normal trim clip that you'd use internally and wasn't sealed in any way, and as water is forces right over the top of it i'm hoping that's the winner, but another 24 hour wait for the sealant to full cure before I re test!! failing this, I might be moving onto drilling holes!! 🙄

 

The hole you see near the bottom has a standard which trim clip in it with a wafer thin gasket on it. It was leaking 'properly' and my initial attempt to just seal it didn't work so I have now removed it completely and sealed the hole with a rubber bung borrowed from the boot floor (With a small amount of sealant for good measure of course!) The clip wasnt realy required as the trim is screwed on at the top and held in place by the light, so I wont miss it!

The white plastic rectangular clip above has been retained but again had a wafer thin gasket which has been replaced with a thin bead of sealant. I wish I had realised this yesterday! But anyway another 24 hour wait to find out where my next leak comes in from!!

[Superleiv]

Hi jonathan! I am dealing with the excact same issue. Just can’t seem to find the excact source of the water. The whole car is stripped down at the moment. So annoying! I thought I found it after sealing of the hole with the clip and Phillips screw holding the bumper, but no.. Would you be interested in having a chat about the issue? Please contact me on Facebook, my name is Leiv Thomas Faulkner.

[jonathanca14]

Hi Leiv, I dont use Facebook I'm afraid.

I purchased a cheap inspection camera on amazon and had a look up the pillar above the light and noticed that there was rust around the top screw in the plastic trim, and I could see drips passing through on the right hand side. So I have removed these and sealed the hole, but I also noticed on the camera that there was a little water coming from higher up, this can only be from the seams tat are well documented by the gas struts. and just above, although I thought I had sealed these I dont think I used a good sealer so have cleaned it off and redone. Ill give it 24hours and wait to see if that fixes it!

[jonathanca14]

I've also ordered a new boot seal from Lexus as mine looks a little compressed and doesn't quite seal correctly allowing water to get past it with heavy water flow. 

[Superleiv]

I see! Nice approach. Probably smart to be systematic about it. After some inspection inside the boot while raining yesterday, I suspected that leak may come from behind the rear bumper. I removed that today, and applied sealant wherever I suspected it may leak. Will be interesting to see tomorrow if it will pass my water test. I also applied sealant around the clips holding the plastic trim next to the light, as I saw the same as you. Some discolouring and rust presumably around them. 
 

please keep me updated! Very interested in your progress! 
 

[jonathanca14]

Small Update, fed up the bumper came off again today and I traced the leak I was looking for to the small bumper bracket below the light, I'm not sure if I've fixed it as in removing it the left hand retaining clip snapped. Even wit it off I've no idea how you'd remove it without damaging the clip.What I would say though is upon removing, there is a small gasket on the 10mm bold between the bracket and the body, this was soaked and when you squeezed it water was bubbling out. I've sealed it all up and left the bumper off so Ill check it again tomorrow afternoon to see how I get on... (Excuse the rough sealant, I pumped plenty in to try and eliminate a future leak!) I also sealed what was left of the retraining clip and the 10mm bolt. 

When I felt the bracket before trying to remove it felt a little loose whereas the other side was solid, so I haven't removed the other sides bracket (and I had no leak there) but just sealed around the top again in an attempt to prevent a future leak. 

[jonathanca14]

Random question - found these whilst hunting, on the left hand side, anyone know where they may be from? Wondered if it was a clue toward another potential leak!!

 

Also made sure my sunroof drains were clear yesterday front and back which they were, however in testing I was a little over exited with the watering can and ended up getting the sun roof under tray quite damp 🙄 luckily we had a warm sunny day today and its now fully dried out! This lexus leaks enough on its own without me helping it 

[Superleiv]

I sealed the same bracket, and also used a lot of sealant to try to make it dry. I used some time yesterday to study my leak, put my garden hose on the back of the car  and I sat inside to watch where everything came from. What I learned is that I have two leaks. One is a steady drip from somewhere up the c-pillar, not possible to see because of the extra panels. The other one very easy to see, was around the ventilation boxes on both sides. Will use sealant around those to tomorrow. 
 

when it comes to the steady drip, my next plan is to seal every body seam one the back in the outside of the c-pillar. It may be tiny holes in the seam, and I will try if I can feel those. I will need to remove tail light, plastic panel next to it and the rear bumper. 

[rich1068]

Sorry, without going through your previous posts, have you removed and resealed the roof bars?

Here's my watery adventure.

 

[jonathanca14]

On 3/23/2020 at 8:48 AM, rich1068 said:

Sorry, without going through your previous posts, have you removed and resealed the roof bars?

Here's my watery adventure.

 

Thanks Rich, Yes I did reseal the feet following reading your post a few weeks back - This solved the upper leak which was appearing near the boot lift motor but not the rear boot compartment leak 🙂 Thank you for your post though as your post was certainly part of the solution!

 

[jonathanca14]

OK Folks, I think its fixed! 

So sealing the smaller of the bumper brackets did nothing (Well it might have done something but there was still a leak!) With the bumper off, lights out and trims removed I tested areas independently and what I hope is my final leak was the only seam I hadn't sealed.

Please see the photo below for where it was, When I looked at it, it was obvious the black paint was cracked on the seam and there were lots of tiny pin holes. there was also a little bit of metal at the bottom sticking out just right to catch water and allow it to pass if not sealed, it was only like this on one side as well which explains why I only had the water on one side. (I've sealed the other side as a precaution just in case!)

I've done extensive water testing today with it still stripped and all OK, but I will put it back together later and continue testing to make sure.

 

[Lager shandy]

Unfortunately just testing with a hose or even a pressure washer ,when you drive a vacumn forms in the car to suck in the water .many a time I used to be driven round in a boot we used to spray the inside with a water dye and use a black light to find the ingress worked most of the time .but you are fighting twisting shells poor sealing etc by body shops .etc which may never seal correctly 

[Superleiv]

Nice work! Looking forward to hearing the results of the water test. I am also beginning to see some glimpses of hope. I thoroughly laid sealant on the body seam from under back of the roof rail to boot opening. Also lifted the boot gasket, so the whole seam was covered. This really did help. Just small drops of water at this point. 
 

Other things I have done is putting sealant under the gas strut, laying sealant around all plastic clips, removing the two screws on the bumper and taped the holes up instead and laying sealant around the ventilation boxes on both sides. This have made the leak much less. 
 

also I talked with my local Lexus workshop, and they were aware of the water issues with the rx400h. They said that most rx400h, will have this problem at some stage because the “glue” they used in the body seams seemed to be of poor quality. Their solution was to do a very thorough water test and then to weld the seams together. He also had some bad news. Because of the crispy seam glue, the pin hole drops can appear in just about any of the body seams. 

[jonathanca14]

I suppose its good to have it confirmed that there factory seam sealing product was rubbish! There are no oaks on the back end now for me, I replaced my gas struts last month and when I did that I used sealant underneath along with thread lock / seal on the bolts to make sure! I'm happy that no water is getting in anywhere from roof rail or side channels or bumper area now and is all completely dry. I did however find a bit of a strange one, on a water test today I found a new very tiny leak but this hopefully was from an obvious source. the small plastic trim around the rear quarter window was coming away from the body, I carefully removed and found there are 4 plastic clips which hold it to the body and then lots of double sided tape. The tape had failed and water was getting in here. I cleaned the panel up and used some good tape to hold back on and put a little sealant in the holes as well to try and close any potential future issues even if the tape fails again! 

 

So far I have...

- Sealed the roof bar foot (and used locktite to seal the bolt threads)
- Sealed the top welded seam in line with the roof bar
- Sealed the seam just above the foot of the gas strut
- Sealed the gas strut foot and used locktite to seal the bolt thread
- had bumper and rear lights out and re sealed all seams. the plastic cover between light and boot edge is not held on by the light only, i have removed all its trim clips and screws and sealed the holes up.
- Sealed the lights 
-Replaced rear boot rubber 
-Re secured and sealed rear quarter light trim

My only area for concern now could be the fuel filler cap rivets. I don't think there an issue as I spent a long time water testing them today, But... The photo I posted a few days where I asked what the weird mettle ball looking things are I think come from the back of the rivets that hold the fuel filler cap on. I'm not sure if water getting in here would find its way into the boot or just leave straight out the bottom of the car, but Ill give it another extensive test tomorrow when my window sealant has dried.

 

 

[Silversalmon]

Hello Jonathan, whilst my own RX is thus far dry my daughter who has a 2007 Honda Jazz has water ingress problems in the boot. Youtube pointed out the weld seams as the likely culprit. I sprayed on some sealant around the seams but she still has the problm. I noticed the issue raised in Honest John.He referred to a cabin vent flap? I havent seen her car but perhaps most cars have such a feature. I took a snapshot of the letter and am enclosing it. Just a thought? I'm very sympathetic to your cause, it would drive me crazier than 3 weeks isolation....

[jonathanca14]

On 3/28/2020 at 7:03 PM, Silversalmon said:

Hello Jonathan, whilst my own RX is thus far dry my daughter who has a 2007 Honda Jazz has water ingress problems in the boot. Youtube pointed out the weld seams as the likely culprit. I sprayed on some sealant around the seams but she still has the problm. I noticed the issue raised in Honest John.He referred to a cabin vent flap? I havent seen her car but perhaps most cars have such a feature. I took a snapshot of the letter and am enclosing it. Just a thought? I'm very sympathetic to your cause, it would drive me crazier than 3 weeks isolation....

Thanks Edward, I did have a leak through the seal of the rear vent which I hopefully resolved when the bumper was off, I actually found it was quite loose, in comparison to the blank on the other side which is snugly fitted. The vent was almost loose! Well worth a check for anyone experiencing issues, sadly this was just one of many on my RX! It hasn't rained for a few days so im waiting for the next down poor to find out if its really fixed!

[Az_17297]

Hi all,

Was reading through this thread - sadly after having a similar issue 18 months ago  on my 2006 rx400h and getting it "fixed" including a refurbished hybrid Battery pack I recently noticed the puddle of water in my boot (out of warranty of whoever repaired it last)... if I was to decide to drill a hole in the boot any advice on which location would be best suited ?  Ppl in the thread talking about strategic holes but would like to get some idea of where that would actually be 🙂

 

Thanks,
Az