2003 GMC/Chevy RB non-pop-top Water Leak

[freezer]

Hey All,

I have a 2003 GMC Sportsmobile with a pop-top/penthouse roof - RB 50 type layout... I've inherited a water issue from the previous owner that I thought I had licked but some recent rain has reveled it to still be active.

I'm only seeing damage in a small area in the interior of the drivers side rear quarter. When you open the left barn door, the back panel of cabinet near the city water inlet has been soaked through a number of times and is showing the usual water damage. It's clear water is soaking up into the panel from the carpet - if my stain reading abilities are up to snuff that is.

I'm not seeing any water damage above floor level... the top and the bed are dry and without marks.

I originally thought the water was spraying up against the bottom of the van from a cracked housing on the city water inlet... and making it's way inside from the pass-thru grommet for the drain line on the water system. I've replaced the city water inlet and the water system is holding pressure. Too, I'm seeing the fresh soaking after a few days of rain and not after use of the water system - It's drained for the off-season.

I've inspected the seals around the rear doors of the van they seem dry ( I opened it up today while it was raining. )

There are a couple of SMB mods that punch through that side of the van - the vent from the water holding tank, the shore power line and the cable socket... but none of those are close to the area that is wet and I'm not seeing water damage in their vicinity.

So I'm wondering if anyone knows of a Chevy specific issue I might look out for or if there's anything else I'm missing. Glad to have any pearls of wisdom before I start disassembling cabinets to get down to the wall of the van. Any tips for pulling out/apart the cabinet with the two fabric-covered sliding panels are appreciated as well.

Thanks in advance!

[Ford_6L_E350]

First, I wouldn't rule out a leak at the top. Water is known for showing up many, many feet from the actual point of entry. Not hard to imagine it could run down a wall and show up at the floor.

Does it get wet with the top up, top down, both?

Any aftermarket windows? A good source of leaks.

Does it get wet when sitting in the rain, or only if driving in the wet?

Mike

[jage]

If it takes a few days to show up, it's likely traveling far.

Any indication it is traveling in the floor sandwich and soaking up only at that point for some reason?

Photos would help.

[freezer]

Thanks for the input - we had a blast of cold air down here so the tinkering has been shut down for a few days.

I did pull the tail light off on that side and found that the seal around the cabin pressure relief vent was popped out on one side. Had plenty of evidence that water was carrying dirt and debris right on in there. Looked like an assembly defect - it had been like that a long time.

It responded well enough to a cave-man style poking-of-seal-back-into-it's-seat with a screwdriver. Today is going to be above freezing so I'm going to see how it likes the hose. If this stops or affects it, I'll take the whole thing apart, clean it and make sure I don't have mold back in there.

Now I need to figure out the best way to re-secure the stud for the tail light that snapped loose during reassembly. Something tells me JB weld ain't gonna cut it. Do I remember something about disconnecting batteries before I weld on the body?

...Water traveling in the floor sandwich - ikes. I guess I neglected to mention that the fluid smells sweet and my heat isn't working. (joke) Oddly enough I got a New Years card this year that said: "Here's hoping your floor sandwich keeps dry in 2012!"

Thanks again for the input.