My 7 year old third generation FIT started accumulating water in the spare tire well. No moisture on the interior side panels or carpet. It remained a mystery until I removed the hatch threshold, spare tire cover and side panels. They are easy to remove, you simply peel their connectors up with fingers or plastic pry tool. Sit in the back and have someone rain hose water all over the back. Then watch for drops.

There are four main leak points on each side: the two 8mm hex bolts that connect the taillight assembly to the car and the two nylon guides that hold the taillight assembly in place.

I made rubber gaskets from a bike inner tube, punched holes and glued them to car with contact cement. These sealed the 8mm hex bolts.

I slipped thin Harbor Freight O-rings on the nylon clips to replace the dry and cracked Honda seals.

 

Good job on fixing it! I had a similar leak in the same spot and after doing pretty much everything you did and not fixing the leak, I found the culprit under the roof trim.

 

What sealing material is applied around the seams in the spare tire well? I need some.

As it turns out I have multiple leaks, some are solved. But I discovered another leak at the seam of the spot-welded taillight panel. The left side panel is generously sealed with “Honda sealing goop”, the right side has gaps in the goop and drips form there.

 

My FIT has not leaked a drop after several storms. I sealed more steel seams than Honda did and I covered some panel holes with HVAC tape. It would have been ideal to find the source of the water intrusion, but that was elusive. I felt good about sealing holes because Honda did that at the factory, I just added to their work. In fact, one of the Honda seals had a pinhole leak.

 

Im fairly certain that those holes in the last photo are meant for ventilation of the car, probably not too important since the vents on the sides will still push air around but it might actually make the car a little too well sealed. Unfortunately all the fits suffered from trunk leaks, might had many strange little ones that took a little while to solve, but that was on my GE. The gk's seem to have a little more problems with quality control than the other generations, had a few more recalls than the other gen's a s well. I would be concerend about it still leaking behind those places you patched up and water staying there, the moisture/ water will most likely not make it to the interior of the car but it will gather and sit there, maybe causing rust issue in the future.

 

i chased leaked FOREVER in my prelude, finally a friend said, drill 2 holes and let it drain out...that's what I did,our cars probably a bit young for that....<note to self> check for water in spare tire well, charge drill

 

Final chapter: The spare tire well water leak spread to include the A-pillar headliner. Although I was willing to occasionally wipe out the spare tire well, I had to act when the A-pillar leak that developed a leak in November. I took the car to my Honda dealer hoping they could most efficiently isolate the issue. Regretfully, after two overnight shop visits and $2000 in costs, the leak worsened. The next step the shop said would be to remove the entire headliner for an additional $1000 with no promise the leak would be fixed. It appears the car body died well before the power train. It's a shame because I loved my FIT and planned to keep it for quite a while. Instead, I decided to trade it in for a new car. Surprisingly, with full knowledge of the leak, I got two $12k offers from dealers to buy the car.

 

the sunroof drains clogged...i sense you always parked outside,never in the garage...what new car did you get ?

 

I do park my cars outside and I did have a moon roof drain issue. Over all, I believe my FIT had a compound problem. The Honda service team fixed a “disconnected” moon roof drain, the other drain(s) were okay. They also sealed a roof body seam and replaced some rubber grommets.

I traded the FIT for a Toyota Corolla Cross Hybrid.

 

A major problem with a leak is that the water condenses onto the interior glass. In the winter, that means I have to scrape ice off the inside of the windows. I've never owned a car that leaked, except for this 2015 Fit, and I've owned 42.

 

every honda i ever owned leaked somewhere!, usally the swimming pool of a spare tire well