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Water on the drivers side front floor

I’m getting standing water on the drivers side front floor. The air conditioning drain hose was plugged, that was cleaned, but still getting water in. The service dept at Mitsubishi is stumped, they say when the air runs, it’s draining fine but when they ran it through the car wash it got water in again. That doesn’t make any sense to me because I drove it for 3 days, didn’t take it through the car wash, it didn’t rain, and by the third day the floor was totally soaked again. Any help would be appreciated, as Mitsubishi wants $1200 just to take off the HVAC case to see if they can find where the water is coming from.

I would first look to make sure there is not a leak (condensation) from the A/C

What Is The Model-Year Of This Mitsubishi Endeavor ?


It’s a 2004 XLS AWD

It Is Imperative That The Service Technician(s) Take Advantage Of Mitsubishi’s Own TSBs (Technical Service Bulletins) Pertaining To Water Entering Vehicle, Especially “Water Leaking Into Floorboard Area” (2004 - On Endeavor).

Why reinvent the wheel ? Have the workers consulted the TSBs ? Mitsubishi has a lot to say about water leaking into Endeavors. I count eleven bulletins, including revisions of bulletins covering this topic.

Popular water leak sources include leakage at the roof rail body seam (water runs behind headliner), which involves removing the roof rail mounting covers, applying sealant to the seams and replacing the covers (which are destroyed during removal).

An HVAC drain blockage can cause a leak or it could be a deteriorated HVAC Case To Bulkhead grommet.

An interior water problem I’ve had experience with (GM vehicle) is outlined by Mitsubishi and involves possibly any of the car’s 4 doors. I fixed my leak by following a similar procedure outlined in a Mitsubishi TSB that instructs technicians to remove the door trim panel(s) and reseal the waterproof film beneath it. That film is put there to channel water outside the vehicle. A void in the sealant that secures it will allow water to run onto the floor. I had lots of water on my driver’s side front floor and and located (with a hose) the leak myself and stopped my leak in short order.

Since you get water leaks without rain, I’d strongly suspect the HVAC case drain or the drain’s grommet (mentioned above). A five page TSB for vehicles, including 04 Endeavors outlines repairs. The drains can plug because of external debris entering the vehicle’s cowl and a new screen is available after the junk gets cleaned out. The drains can plug because of internal foam packing material has been found to be a problem. The HVAC case grommets deteriorate (as mentioned above) and cause water to leak onto the driver’s side floorboard. $1200 seems high to remove the case. Mitsubishi listed the job at just under 6 hours labor to do the job when it was needed for vehicle still under warranty. Mitsubishi recommends always replacing the grommet when the case is removed to clean out debris / foam.

You don’t mention whether or not you’ve got a sunroof. There’s a TSB (glass adjustment)for leaks there.

Careful diagnosis using the TSBs as a guide is key. If your people aren’t utilizing the TSBs then they’re just flying blind, tying up your car, and taking your money. Get with a Service Manager and ask to see the TSBs. They might owe you some good service.

Should the dealer be correct about the leak at the car wash, I suppose you could have two issues at the same time, but that seems unlikely.

Sorry for the rambling. I hope this gives you some ideas. Ask more questions and we’ll take it from there.


This gives me a great place to start. I agree that it seems more likely that the problem lies with the HVAC since the water appears when we haven’t had any rain. You asked about a sun roof, it does not have one.

Again, thanks for the info!

You’re Welcome.