So I have had my 92 for a couple thousand miles now and was happy to find that for the most part it was water tight, until recently that is...

After I bought the car I brought it to the car wash to hand wash it and inspect for any leaks, and the only thing I could find was a very minor dribble on the top of the drivers side window where the seals meet. After a little adjustment, problem solved. All in all the top is in great shape.

Just recently we had a couple days worth of torrential downpours and thunderstorms. I do not have a garage where I currently live so the car sat out in the weather the entire time. It was over the weekend so I never even drove the car or even sat in it for that matter. I hopped in it monday happy to see that I had dry seats and all was well, until I got to work and noticed moisture on the floor mat. Upon closer examination I noticed it was not just moisture, but the entire floor mat and floor itself was swamped!

I got home after work and immediately researched what this could be and came across quite a few references regarding the water drains and how they could back up and cause leakage inside the car. I located the drain under the car on the drivers side (the only side that was wet) and from what I can tell it is free and clear of any debris. Where is this drain located on the inside of the car? Perhaps I need to examine it from that end as well. I took a quick look and was not able to find it without removing anything. Do I need to completely remove some of the carpeting to find it? I plan on taking the seat out this weekend to try and help it dry out, but I would like to solve this little mystery before the next thunderstorm rolls in. Any hints or tips would be appreciated.

 

Pull the package tray carpet up and see if the padding is wet under the carpet back there. It could be the rain rail or one of the top drains. The water will run down behind the seat to the floor.

 

Did as you said and there is absolutely no moisture behind the seat. The padding is completely dry and it is only the floor itself that is wet. Really strange, and for the life of me I cannot figure out how that much water got to the floor...

 

Is the drain hole open behind the shoulder belt on the driver's side? Blow through it with compressed air from the hose in the rear wheel well to clear it. Also check the windshield pillar rubber and make sure the drain channel isn't clogged on the driver's side.

If the windshield has ever been replaced it could be leaking above the dash on that side, too.

 

Ok, well the weather has sucked so I have not had time to take anything apart yet, but this morning I woke up to yet another flood on the drivers side. I noticed the weather strip/drain that runs from where the top meets the a-pillar and runs along the front the the door down to the kick panel. I decided to pour some water of my own down the hole to see where it ended up and I think I have found the culprit. The water started to flow right out onto the kick panel area where the bottom of the door fits. I have my suspicions that it was also flowing the other way right into the car, as that is right where most of the water seems to be concentrated. My question is this... where is this water in this drain supposed to be going? Is there another drain under the car right behind the from wheel? Once the weather clears up a little I will take the kick panel off and pull the carpeting back and have a look.

 

I found this service bulletin Miata Technical Service Bulletin that I thought would have answered my question. I cannot locate these holes ANYWHERE on my car. I look at all four corners where the jack points are located and could not find them. I probed the area with a coat hanger hoping to find a soft spot where it might be covered and found nothing.... extremely frustrating!

Ok, that picture is a little deceiving the holes are actually where the floorboard weld meets the body panel EXACTLY where the jack marks are. Got it opened up and it has been draining for the last 15 minutes. I'm hoping there is also a drain connected to the floor area of the car as there is still a good 1/4 inch of standing water in that area.

 

I think there is a rubber plug under there.

Unbolt the seat and remove it. Then take the door sill covers off and the lower seatbelt anchor bolt behind the door opening. This should allow you to lift and fold the carpet back towards the trans tunnel. The batting material will be soggy and won't dry unless folded back. If yours is like mine, one of the factory holes cut in the carpet will fit over the gearshift lever if you pull it just right and then you can set up a fan blowing on it. Because the carpet bottom is molded plastic it will hold the water underneath it and never dry out unless you pull it up.

 

I had places to be yesterday so I brought the car to the car wash, took the seat out and vacuumed the water on the surface and under the carpet. I ended up removing the insulation cause it was basically water logged and I figured I would need A LOT of time with a fan to dry that out and since I did not have the time or the patience I just removed it.

It's dry now and the next big rain will tell me if opening the drains solved my problem. Ah, the joys of a convertible. Can't wait till I find a decent deal on a hard top.

 

rxman55 here. Just reading your post about leaks and my 93 has a leak but different than yours, mine is a large amount of water in what sounds like the passenger car frame. I can hear the water sloshing around. Any ideas about this problem? It does seem to dry out after a day or 2.

 

It sounds pretty similar to mine actually. Water can accumulate inside the rocker panel below the door on either side. There are drains under that panel that get plugged up. (very poor design in my opinion) It is hard to explain but they are on the edge of the weld seam where the jack would normally fit to jack the car up. Very difficult to see laying on the ground looking, but you can tell where it gets just a little wider on that seam right where the notches that indicate the proper placement of the jack go. If you take a wire coat hanger or a flat head screwdriver and poke it up in those locations you will free up the debris and water will flow out as intended. There are 4 holes on each side of the car, 2 behind the front wheel and 2 in front of the rear wheel. Those holes are designated for the rocker panel only. There is a larger drain in the rear that is fed from the rain rail at the rear of the top, but that does not drain into the rockers.

** I should add although I did not hear the water sloshing around, I removed the kick panel and could look down into my rocker panel and see it 3/4 of water. My theory is that it filled and overflowed over the little lip onto my floor. Next beg rain should prove my theory right or wrong.