My 04 Endeavor just started collecting water on the driver side floor a few weeks ago. Didn't think much of it since my wife did accidentally spill her drink the one day. 3 weeks later, notice water again. Used shop-vac to collect water and had almost a gallon of water.

Quick Google search and found these threads. I also found what seems to be another good resource and thought I would share.

Mitsubishi Endeavor LS I have a 2004 Mitsubishi Endeavor and - JustAnswer

VanB

 

I believe that the problem now is a miss understanding of the leak. Yes water is now flowing again through the evaporator tube, as it should. The problem now is not a clogged tube but there is no seal left between the tube and the fire wall! The water is now flowing inside the cab and not outside to where it belongs. I discovered early on that the dealerships said " The $1,000.00 charge is to do all the work necessary to replace a $1.50 gasket". This has to be a seal that blocks the space between the evaporator tube's end and the firewall. Otherwise water can fall between the end of the tube and the firewall and fill up your floor pan?
I stand by my Post with the instructions and accompanying pictures. My floor pan had more than a galon of water! Now I am on my second summer season with a bone dry carpet? Not bad for $6,50 wouldn't you say?

 

I believe that the problem now is a miss understanding of the leak. Yes water is now flowing again through the evaporator tube, as it should. The problem now is not a clogged tube but there is no seal left between the tube and the fire wall! The water is now flowing inside the cab and not outside to where it belongs. I discovered early on that the dealerships said " The $1,000.00 charge is to do all the work necessary to replace a $1.50 gasket". This has to be a seal that blocks the space between the evaporator tube's end and the firewall. Otherwise water can fall between the end of the tube and the firewall and fill up your floor pan?
I stand by my Post with the instructions and accompanying pictures. My floor pan had more than a galon of water! Now I am on my second summer season with a bone dry carpet? Not bad for $6,50 wouldn't you say?

 

A/C was working fine but while going around turns you can hear water sloshing around then noticed water dripping and passenger side floor mat
wet. Figured A/C drain clogged. How to get to drain to unclog? I have a
2004 Endeavor LC

 

I too own a 2004 Endeavor. Had the same problem. Check out the forum thread "Water leak while a/c is on" and look for my (John Paul Russell) post with pictures. Hope it helps and good luck. Dealers want near $1,000.00 to fix problem. Cost me 6-7 bucks!

 

Thanks to John Paul Russel whose pics allowed me to solve our inside A/C water problem. Ours was doing the same thing and after checking the internet I resolved to going the whole 9 yards and remove the dash, evaporator etc. since nothing else really worked. After a lot of crawling around I found the drain hole and ran a wire up the hole to try to dislodge whatever had it stopped up. I got a few drops of water but not the gush I expected. I ran another smaller tube up there but it's such a tight space I couldn't tell if I did anything constructive or not. It worked for a while but the thing finally quit draining alltogether. The system was full of water and would slosh around and I guess the cold water was causing even more condinsation inside to the point we had to shut it off. South Louisiana in Aug. and no A/C. Worse yet the floors were saturated and it was really steamy. No way we had 1k bucks for the dealer and after starting the disassembly to get to this drain I knew it would be hours if not days to fix this. I went back further into this forum and saw John Paul's pictures that showed me where the drain was located in the interior. His method seemed pretty labor intensive and this is a small space. I wanted to actually see what was behind the firewall and inside the housing so I drilled a 7/16" hole. I wasn't prepared for the gallon or so of water that kept comming out of the hole. After it drained I could see something but really coulden't tell what it was untill I took a little dental type tool and poked around in there. That thing was full of all kinds of debris. Old decomposed leaves, bugs, road grime, mud, insullation and plastic. I wish I had of took a picture of it. After I dug all the crap out of there I took a H2O blaster which is like a big syringe and flushed the chamber/ plenum whatever out untill I felt I got it clean and patched the hole withfoil tape. This thing is draining like it should now and I really think this is a good fix compared to the alternatives. I think the gradual accumulation of debris in this area slows down the drainage to the point where the condinsation starts backing up and looks for a place to go. As long as it can freely pass to the outside the interior will stay dry. To anyone else who tries this: Have a large container handy to catch the water or your going to soak the carpet.

 

Horton,
I started to do exactly what you did. What I did was a lot more labor intensive and my back killed me for to weeks! I was afraid that if I drilled a hole where you did that I still may not be able to get the water to go outside the fire wall and/or the water would still leak between the exit tube/port and run back into the interior. I am very happy that this worked for you. It sure seems like the design was simply sour to begin with? God Bless!

 

Anyone tried this on a galant? I have this same problem with my galant.

 

At one point I maanaged to run a coat hanger thru the tube to make sure I was on the right track and clear the tube. This is a bad design. Better filtration might prevent this. Also when I first started trying to fix this mention was made of running a smaller O.D. tube inside the existing tube. By having at least some limited access to the inside of this box that might be possible also but it seems the tube would have to be a perfict fit. Now on to my squeaky back hatch. Cant quite place it. Any ideas?

 

I wish I had of seen this post two weeks ago when I discovered the water on my passenger side floor. After calling two out of town Mitsubishi dealers (as the local dealer I purchased the 2008 Endeavor from closed over a year ago), and waiting a week for a response before being told that I was 3000 kms past my warranty, that there is nothing either would do for me. Not only that, but that they knew nothing of this issue. Seems like everybody who ever owned a Mitsubishi has heard of this issue, funny the dealers haven't ??? Since I work at a shop with a licensed mechanic he tackled the issue on my behalf. After peeling back some carpeting and removing different panels he assessed the situation and felt that drilling a hole as you have shown in your photo was probably the first thing we should do before attempting to remove HVAC parts etc. Immediately after drilling the hole water started gushing out. After draining off about a litre of water into plastic cups, the mechanic installed an airhose to blow the rest of the debris from the line. (Yes, there was black flecks of plastic debris in the water that came from the condensor but no leaves or outside debris of any sort). Next he siliconed the hole he drilled and ran the a/c until we seen water dripping underneath as it should. The next big problem was tackling the water that had accumulated on the floor boards to the point of soaking the entire passenger side of the vehicle - front and back. This required removing the passenger front seat and all the carpet, underlay and foam as it pooled under the foam against the floor. Still not dry as of yet and we have over a gallon of water in the bottom of the shop vac, and the smell is horrible. Bad time of year to run the heat but we may not have any options if we manage to get it dry enough to re-install the carpeting before the end of our work day. Given that we are still in the process of clean up, I can't say forsure that this is the perfect fix, but while running the a/c to check for leaks, it seemed to have work. Keeping my fingers crossed that it is more then just a temporary fix.