Jimny boot filled with water after driving through torrential rain (pics inc!)

Very interesting on the alcohol content / blue colour bit! And yeah, that makes sense about the one-way valve. It failing might explain my fluid draining but not it going into the car itself. This weekend or next I'll pop the back door cover off and take a proper look to see if there's an obvious split anywhere. I was going to do it anyway to stick some sound dampening / lanoguard in there so two birds with one stone...

Big thanks again, will post if I find anything.

Investigated more today. I refilled my wiper fluid and intentionally parked on a steep hill. I could see that the wiper fluid was forming drops and leaking out the back jet (outside the car). That would suggest I have the same one-way valve failure everyone else complains about. Should be an easy fix.

But it does imply that my boot water leak is not related to wiper fluid. Not least because when I checked the car I could see a little drizzle of water in the back corner again and that appeared despite my wiper fluid being empty. Given I power washed yesterday it could be that it just took some time to seep through and it is indeed to do with the boot seal / door not closing fully. I'll muck about with it once I've got some free time.

Fluid leaking out of the washer jet to the outside is probably not the one way valve, it's designed to let fluid out, just doesn't allow reverse flow, i.e. air back in to stop the pipe from draining back in to the reservoir.

A leak from the door, window or roof is most likely and yes, it might take time to seep through and pool in the boot. If it had been leaking through the weld, you would have thought it would have been there straight away.

Robin

Still baffled by this. So the whole wiper fluid thing was a distraction but I've replaced the valve and I'll see if it my reservoir drains out or not. Also sound proofed both my doors and the back so woop woop.

But as for the leak, I jet washed again today and there were immediately a few small drips of water in the back driverside corner (it was bone dry before I started, hasn't rained in Glasgow for about 5 days amazingly). It was hanging out where the metal of the boot panel meets the plastic trim. So I am now minded that it must be dodgy factory seam sealing essentially where the rear wheel arch meets the bottom boot panel.

To properly investigate I'll need to take the back seats / panels out again (I seriously hate that job). I may just run a bead of tiger seal along it to remove any doubt.

The closest thread I can find is this one by Halford (www.bigjimny.com/index.php/forum/6-jimny...oot-floor-rust-again) - i.e. magic drops of water appearing in the back lol.

Will drop him a message and see if he ever resolved it.

never did get to the bottom of it - but maybe Kirkynut  was onto something

Thanks for responding! I think he's right. Condensation leads to a baseline of water just "being there" and then dodgy seam sealing / only being spot welded means that if it doesn't outright leak into the cabin (like it seems mine is) then moisture still sits there and rots it out.

The solution would therefore be to properly seal the seams and apply insulating material or similar to reduce condensation forming. Then apply some sort of rust preventative stuff on the underside of the vehicle, maybe lanoguard.

It's telling that, aside from the jack area and rear corners, the next most common place for boot panel rot is around the seatbelt anchor points. Likely because its got spot welds but nothing to keep the water & salt from just sitting in the gaps between them.

At the weekend I removed the rear plastic panels and took a proper look. Went under the car too. My conclusion is basically unchanged from above.

Improper seam sealing can allow water into the car that then flows backwards as the vehicle is in motion, collecting in the rear corners and also in the rear jack tray. Depending on how well your vehicle was sealed this may be more or less of a problem, on mine it appears to have been an issue but I've now wire brushed the rust and sealed over the factor seams with Puraflex 40.

Then there's the seatbelt anchor points in the back which rust out along where the boot crossmember is welded. The water likely sits in the spot welds. This could be prevented by using a good creeping underseal like Lanoguard or Dinitrol if the vehicle is new / not already rusted.

Further, the idea that the jack tray gets heated up by the exhaust back box seems very plausible to me. I drove 40 minutes on a cold day and you can feel just how warm the panel gets. Not burny hot but enough to attract condensation I am sure.

The only thing left to do is drive through a bunch of puddles and see if waters gets in again... Even if it does at this point I will just accept it and move on. The amount of rain I went through to cause the aquarium in the back was crazy and we only drove in that weather to get home because we needed to be back for work!