Hello! I've got a 1991 Mazda Miata with 168k miles and in manual. It's been a great car to me so far, but I've started having a funny issue.
All drains (rockers, rain rail drains, etc) are all clear, but I hear water sloshing around! It sounds like it's coming from directly behind my head and is most common when going over bumps or slowing down. All the drains drain water perfectly, so what do you think I'm hearing and what can I do about it?
I've considered the gas tank, but since it's baffled it shouldn't be making noise especially when full, I'd like to think.
I’m sure it’s water collecting inside rocker panels. It’s a known problem on some Miatas. When assembling bodies, factory applied too much sealer at the bottom seams. As I remember, there is a recall addressing this issue. Look it up. I think it applies to early NBs.
Anyway, … when you look at the bottom, … drain holes look perfectly clear - open, but they are not. They are plugged, on the inside, with blobs of excess sealer. You have to punch those out. Try it, … punch those drains with a stiff wire. If water comes out, you just solved your puzzle.
F.S.
OK, … sorry, I missed the year of your Miata. But here is some stuff pertinent to NAs, all 1990 - 94 Miatas: https://www.miata.net/garage/tsb/s034_94.html
F.S.
Yes for sure! I knew about this issue prior to purchasing the car, and sure enough, that's not the issue. I enlarged the drains as per the service bulletin with a punch.
When water gets on the top, the drains flow free. Meaning the water getting on the top exits exactly how it's supposed to, which is why I'm so stumped haha
All drains, seatbelt tower/rocker drains are perfectly clear, that's why I'm lost.
Well, … now we are lost both! I just can’t imagine where else that sound you hearing is coming from. There is no other possible place in a Miata’s body that liquid can collect. Most baffling, …
F.S.
Check the door post/pillar. Check the body rails under the door and inside the door itself.
Yes I've checked both of those. Door itself is clear as well as both rocker panels. If you grab the car next to the rain rail and shake, there is a sloshing sound right where the gas tank is positioned.
The rocker drains/seatbelt tower drains are completely clear and water drains great. It's not like an "ocean wave" noise, its more like little sloosh noises occasionally.
You may have already tried this as well. It may sound goofy but is there a change in the sloshing sound that would relate to how much gas is in the tank? You keep mentioning the gas tank so I'm curious if you mean the tank itself or the filler neck/cap area. And not to insult anyone, but I've had friends stuff things in odd places in my cars that stink or make noise. By that I mean you have checked all over, in and under everywhere where a half full liquid container might be? Do you carry a container of coolant in the car? I know it's retarded, but I've overlooked stuff like that myself.