[ToadVine]

Hyundai

Shouldn't be too hard to do while they are away checking on something. If you've never done any kind of interior work and aren't comfortable popping the sill panel then you'll just have to be extra charming and get them to do it for you.

Or, skip the charm and just tell them you won't consider buying it until you are sure that this well-known water leakage issue is not present. If they start hemming and hawing, then you have the answer.

 

[ToadVine]

How to find a mysterious leak:
1 Place a large window fan in a window, blowing inward.
2 Seal off as many openings as possible with tape and plastic sheeting.
3 Spray the outside with soapy water.
4 Follow the bubbles.
Yes, it worked for me.
No, it didn't blow the windshield out.

 

[ToadVine]

I have never had a tonneau cover on my truck and it was still wet under the back seat on the drivers side. The suspicion seems to be the two slot drains at the lower corner of the back window. If parked down hill slightly I could see that all the water from the cover could wind up there and maybe the quantity of water from the cover could make a difference.

As for my truck the dealer said they found the leak that left the back drivers side wet AND an additional leak. They have repaired them both and will have my truck back to me today. They were caused by faulty panel seems is what I have been told.

Maybe you could get whoever fixed it at the dealership to point out the exact locations of the leaks. If they can't show you because the truck has been reassembled, perhaps they could point it out on the diagram in the service manual.

 

[ToadVine]

... According to service guy, the tech had a bit of a personal vendetta against my leak because he couldn't figure out where it was coming from. They ended up sealing every unsealed seam, and re-sealing others. I guess they just repeatedly ran the truck through the carwash to verify it was still leaking. They settled on the culprit being a couple bolts in the rail system on the top of the cab. ...

I believe that this is the first time we've seen this theory (although I didn't go back and re-read the entire reply chain.) But, I would give this idea some credence since it sounds like the tech really wanted to solve the mystery rather than just 'get it out the door.'

 

[ToadVine]

Yep, adding more welding is not a good solution. As Celltech noted, use an automotive seam sealer and lots of it. I choose to use a butyl adhesive plastic flashing tape that was designed for installing home windows. Pick a premium tape rated for very low temperatures. I choose to use tape because it can be installed without dropping the fuel tank.

Did you run into any problems with taping a dusty surface (or even worse, greasy)?