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.

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.

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!

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.

Thank you for all the information you provided! Really helped me a lot in the process of finding the leak. As with many others, I realised I had a problem when the carpet in all the foot wells were drenched in water. I stripped the car for carpet, panels and seats and started the search for the leak. I don’t have a sunroof and soon understood that the leak must have come from the back (trunk area) and poured down to the foot wells. I also had a lot of trouble finding the leak, due to the double and triple(!) panels. My girlfriend sprayed the back of the car with a hose, and I sat inside observing water Pouring down both the sides ( c-pillars), but not being able to see where from because of the double panels. I then bought a inspection camera and slid behind the panels. And happily found the source to my trouble! The clips and Phillips screws holding the rear bumper up, just below the black plastic trimming next to the tail light was totally open! The water just flowed right trough it. I took out both the screw and plastic clip, taped the hole with duct tape (temporarily) and voila! No more water. I also used the inspection camera up along the c-pillar to inspect if I had a problem with the body seam above the gas strut. But from what I could see inside the panel cavity it looked like the main problem was leakage from the two bolts holding the gas strut. Will probably make a rubber gasket and lay between the body and strut and I think that will fix the problem. Hope this will maybe help someone out there! The picture is from thomasN post, but is the clip and screw I took out and taped the hole. Remember to use degreaser, so that the tape sticks well.