[WWEvoX]

My 09 GT was letting in water and I couldn’t find much information on this particular kind of leak. As these cars get older rear leaks like this may become more prevalent. Hopefully this helps someone.

Leak is located primarily in one of the two corners of the car above the rear seats and triangle windows. Mine was on the passenger side. I noticed saturated headliner, water under the rear seats, and my trunk was filling with water when it rained heavily. When it would rain the water was actually visible dripping down the back panel under the removed pillar in the pictures.

I found and followed this YouTube video:

He was having a similar problem. This however did not fix the leak and made my hatch look a little sloppy.

I thought the water was possibly getting by the gasket and getting into the seam to cause that rust. As you can see in the second photo the water is still coming through where the two panels meet. Able to see when pulling down the headliner. This was where the leak was always coming from.

Slight cracking on the seam going up to the roof drip molding. This is the channel water runs down toward the back of the car to drain. I tried sealing the cracks with Flex Paste. After it was dried I tested with a hose and the leaking was slowed down.

Next I removed the black drip molding on the roof of the car. This was easy to remove as it’s just held on with double sided tape. I cleaned up the tape residue with goo gone.

Finally found the main culprit. I first filled in the scratch I made accidentally with touch up paint and clear coat- so the roof wouldn’t rust. I filled in all cracks again using Flex Paste

There was a small crack starting up front that I also covered but didn’t get a picture. I hadn’t had a leak in the front but wanted to be safe. After some testing the next day I determined the inside was finally dry. Reattaching the drip molding was easy enough with some good double sided tape.

It’s been a few months for me and the car has been bone dry

If water is getting inside your car I would try to act quickly to save your interior and prevent the roof panels from getting wet and potentially rusting out areas that aren’t visible which could end up being hazardous- like the roof seams.

User BrianJ seemed to have had this issue back in 2008 and had it fixed by Mitsubishi themselves.

DIFFERENT Water leak problem...Structural problem

Ok guys, I've had the guides in the sunroof replaced for the water leak by the sunroof button...it doesn't leak there anymore. HOWEVER, there was also water in the BACK of the car...they thought the guides would solve this as well, but no luck. Here's the deal. On the passenger side in the back...

www.club4g.org

I apologize if I’m posting this in the wrong place

 

[Sabertooth^2]

Thanks for sharing.

The way you wrote things, it's a bit of a problem report, bit of a how to (but more of a how I did). If you think this is the spot to post it, I wouldn't argue. Sometimes there's more than 1 right answer, and what fits best is based on the individual reader and writer

 

[SPEEDRACER11]

So glad you finally identified the cause of the roof water leak. Great job! While I owned your GT there was never any evidence of water leaks: no water stains on the headliner or water in the spare tire well. I think you are correct in attributing the leaks to the deterioration over time of the body seam sealer that Mitsubishi used; at least on this particular car. The cars that Mitsubishi repaired under warranty probably had poorly applied seam sealer on the assembly line. On 1991 F bodies GM used structural epoxy between the body panel flanges and then spot welded them and applied seam sealer to waterproof them. It doesn’t look like Mitsubishi used this technique. I wonder if the seam sealer was applied robotically or by hand on the assembly line and what leak testing was performed on the body before the interior trim was installed. Hopefully your GT is still running as nicely as it did for me.

 

[WWEvoX]

The GT has been running great! Truly enjoy driving the car as a daily. Other than regular maintenance, I’ve finally started on retrofitting your old headlights. Did you ever notice there was a plastic piece missing from the inside of the passenger headlight? It didn’t look like it had ever been opened before I pulled it apart. I was thinking of starting a ride thread just for updates. Although I don’t think I’ll be modifying the car much more, I’d like to keep it stock.

For anyone else reading a shop owned the car in between SPEEDRACER11 and myself. They removed the hatch glass to fix a rust spot and didn’t seal the glass properly after putting it back on. I had a few different leaks all at once that led to some head-scratching

 

[TehCimsonFawks]

is this issue just a water leak or a structural integrity issue? My 06 has the same leak. although the leak seems small. I don't drive in the rain alot and park under a car port. If its a failure of the structural bonding material could it cause any other issues further down the road?