13 Limited, wet third row floor carpet, dry everywhere else

[rheld68]

I have read so many postings where owners have the same issue, but have yet to see someone post the definitive location/cause of this leak and the solution........I can and will tear this thing apart but was hoping that someone in this community has had this identical experience that can share the actual solution in hopes of saving me some time and grief. It's our primary family vehicle so I have to fix it quick.

2013 Expedition Limited, carpet / floor in third row is wet. Headliner is completely dry everywhere with no evidence of past leaks. Yes, it has a sunroof, but again, zero headliner issues.

I checked and sealed the roof rack rails, but this felt frivolous given there's no moisture in the headliner.

My next adventure is figuring out the rear quarter/side glass.....it is the venting/opening kind. There is no evidence of water getting between the rubber seal and the glass itself. I didn't actually see any posts where the rear side windows were leaking AND they were this opening style...just the earlier non opening style.

 

[eddytheexpy]

Dumb question but did you smell the liquid?

I know the ELs have a rear heater core, not sure about standard length though, but I don’t know which one you have anyway. If you do have a rear heater core, it lives above the passenger side rear wheel well. That may be your culprit since there’s no signs of a leak coming from the exterior.

Is the wetness favoring the passenger side? If it’s just sorta wet you may not be able to smell if it’s coolant since it’s fragrance is probably watered down with 11 years worth of being a carpet haha. Pull the trim off and look around for puddles.

If that’s your guy, don’t despair. I understand the job is straight forward unlike the hellish nightmare of the front heater core.

Let us know what you find!

P.S. if it is the rear heater core, for the love of god, don’t use stop leak! A previous owner of my vehicle put stop leak in the coolant and I needed to replace ~$800 worth of parts because of it clogging things up. Yesterday while replacing the oil filter adapter gasket I found the leak they fixed with it, it was that $20 gasket. Don’t be him and cause $800 of damage to save $20.

 

[rheld68]

It's a standard length (not EL). Coolant level is/has been unchanged. I'm not sure about a rear heater core on these but I can certainly look into it. But I'm gonna bet it's not what's going on because no antifreeze smell and unchanged coolant levels.

 

[eddytheexpy]

Ok, I looked into it in the meantime and the non-EL models don’t have the rear heater core so disregard my comment. Aside from that I can’t imagine what other ways water could sneak in without leaving some obvious evidence.

Like you said no one posted their solution if they ever found it so if you find it, don’t forget to help out the forum and post your resolution! Happy leak hunting!

 

[Hardcase60]

Hose/coupling for the rear window washer? SWG (Sophisticated Wild Guess).

 

[bloodhound]

If you have rear heat, you have a rear heater core regardless of EL or not. But I would certainly think you would smell the antifreeze if that's what it is.

 

[rheld68]

Yeah it’s definitely not antifreeze….and not soapy either (washer fluid). My plan was/is to take the inner top trim piece of the C pillar out and run the hose over to see if I can find it. This assumes it’s it’s infiltrating the roof rails (which I have now “sealed”) and/or around the rear quarter glass. Unfortunately, I have not been able to do this yet. But I’m still hoping that someone can help me save some valuable time be sharing their resolution to this specific problem which appears to not be an isolated incident with the 07-17 Expedition.

 

[peeteri]

No roof rust?

 

[Stingray]

Check your rear cooling condenser drain.

 

[Stingray]

Previous Post,

Rear A/C Unit​

 

[rollinstone]

For the first time couple months ago I noticed water droplets running down the inside of the left side rear vent window. It wasn’t much, but no one wants water coming inside. I got some thin weather stripping and applied it around the top seal. That seems to have stopped the water from getting in.

 

[rheld68]

So far, I’ve traced the water on the drivers side as far back as the bottom bolt for the third row seat belt, but on the passenger side there’s no evidence that water/moisture is that far back, just damp where the plastic trim meets the carpet in the third row foot well. Because the drivers side was way more wet than passenger side after light rain yesterday I pulled the top interior c pillar post trim out thinking for sure it was leaking around the rear side glass…..got my dad to help me running the hose over it and could not find any water infiltration.

The search continues.

 

[rheld68]

I believe I’ve solved it!

It’s the body seam in the rear wheel wells directly over/infont of the rear tires. I’ve sealed them and has been dry since. I should note that I had already checked the sunroof drains & sealed the roof rack rails (despite the headliner never being wet). But I was still getting water in the third row floorboard. In hindsight, It would occur when driving in the rain, and when I washed (I always wash out my wheel wells).

I have access to an infrared camera (this particular one is from Snap-On) which has a procedure for finding leaks. In this procedure, you start and run the vehicle with the heat turned on and running at full blast. While inside the vehicle and interior warmed up, you use the camera to check for cold spots. While this did show some cold spots on either side of the third row floorboard where the side plastic meets the carpet, i wasn’t sure that it was really telling me anything.

So, I exited the vehicle, left it running, and looked for hot spots around various places where it could conceivably leak. That’s when I found the seam in the wheel well. To be fair, I had considered it as a possibility before the procedure but felt like it was unlikely. With no other obvious locations being revealed, I decided to seal that seam and see what happens.

As the son of a self employed mechanic who’s been fixing cars for his whole life, I’m pretty determined not to half ass anything (unlike Ford), so I start with using 3M products for sealants whenever possible. In this case, body sealant and spray on rubber.

I scrubbed the wheel wells as clean as I could, let dry over night. Put it in the shop, removed jacked up (put in jack stands) and removed rear wheels. Used compressed air to blow out/dry, remove any loose dirt or material that remained. Forced the the sealant into the seam and filled the gap so that it wasn’t a crevice.

The body sealant is ready to “paint” fairly quickly. I sprayed the seam/body sealant with no less than 4 light coats. I also sprayed the rest of the factory spray textured area just to make it look a little better.

After a week of dry weather, it was finally driven in and sat out in heavy rain. Totally dry. I verified by washing the car with my electric pressure washer (including the wheel wells) and it remained dry.