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Toyota Repair/water infiltration


Hi Ted,

My wife has a 2007 Avalon with a moon roof and recently discovered that the front and back floor pans on the drivers side are sopping wet with no apparent reason. I have no idea how long the water has been there.  I'm guessing several weeks to a month based on my wife's complaint of mildew odors. Both passenger side pans are bone dry. There has not been any recent work done on the car. So far, I've done these things to check it out but have not found a leak:

I opened the moon roof that hasn't been opened in years and found the channels dry as a bone.  The rubber seal looks like new. The overhead padding inside around the moon roof and throughout the car is bone dry.

I checked the trunk including the spare tire well and it's dry as a bone.  The rubber seal looks like new.

I checked the AC drain hose and condensation runs freely with the AC running. I blew it out with an air compressor anyway.... just for good measure. I also checked under the dash. It was not wet but could have dried.

I removed the windshield cowl to check for leaf accumulation (none to speak of) and poured water down the windshield and it drained freely on both sides behind the wheel wells.  I blew them out for good measure anyway.

I checked the three weep/drain holes at the bottom of each door and none were clogged.  I blew them out for good measure anyway.

I checked the rubber seals on each of the doors and, aside from very minor fraying at the top rear of each door, they are all in good shape.

So now I'm at a loss.  We have had lots of rain this summer but gee wiz, there just doesn't appear to be anything that would get both the front and back driver's side floor pans wet... and nothing else.  And, since there is a considerable hump between the front and back floor pans, I'm trying hard to imagine what could cause both of them to get soaked.

Aside from sitting in the car during the next storm and waiting to see where water might be coming in, do you have any ideas where the water might be coming from.... things to check.... things to try....?

Thanks for your help!

hello, it's possible that the drain hoses or one hose on the driver's side for the sunroof are either clogged or disconnected, open the roof and slowly have someone pour water from a bottle or hose directly into the drain channel on the left side, try to park so the left side sits a little lower than the right to keep the water on the left, there are four drain tubes all together, one on each corner, make sure the water fills the entire channel on the left so you can check both front and rear drains, the water only has three places to go, either drain through the exits on the bottom like they are supposed to, drain inside because the channels fill up due to a clogged tube or drain inside the headliner due to a disconnected drain tube.  

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Ted Ritter


I have more than 28 years experience as toyota technician, I will be able to answer most questions related to the Toyota product line up to the present year models,I am located in the US but welcome questions from other regions of the world. When asking a question please provide specific information: year,model, engine,transmission information. Provide as much information as possible including a brief repair history if possible. I have been a volunteer here for more ten years an have answered over 16,000 questions helping Toyota owners with their problems and save thousands of dollars without any compensation, some of my answers are published on many other websites including google and various automotive forums. DONATIONS ARE VERY MUCH APPRECIATED, IF YOU HAVE RECIEVED HELPFUL INFORMATION PLEASE MAKE A DONATION. AS OF TODAY (JULY 22, 2014) ALL REQUESTED GRAPHICS, ILLUSTRATIONS, DIAGRAMS, PHOTOS, WILL REQUIRE THE MINUMUM DONATION UP FRONT.


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