As the weather cools, I noticed recently I have noticed condensation on the inside of my windshield. As soon as I wipe it off, it seems to reappear in minutes. There seems to be no other wet spots in the interior of the car either. Anyone deal with this? Here is a picture of it half wiped off. None of my other cars parked outside have this.

 

Plasticizers emanating from the interior plastics deposit on the windshield over time. Sitting in a hot sun exacerbates this. These deposits attract moisture and could be your cause of condensation. A really good inside windshield cleaning may get rid of it.

If the issue continues after cleaning the windshield, you may have a slightly leaking heater core - slimy condensation on the windshield is often the 1st sign of that. Have you smelled coolant inside the car?

 

it doesn't take much moisture to make a fog on the window. my FC fogs up, i'm not 100 sure why, but it seems to be that the rear window leaks a bit, and the hatch fame fills with water, which is kind of funny

 

Go to the dollar store and get some of those de-humidifiers, put one in if its going to be parked for a bit and take it out when you drive. This can also be due to a leaking heater core. Check your A/C drain and see if there are any coolant stains from it dripping out or sometimes you may notice a sweet smell when you have the heat turned on.

 

you got a leak or some squirrels are getting hot and heavy in there

 

I'll try this first...no weird smells or anything. The car has been parked since 2019 with me rolling the car around to wash it periodically or air it out.

 

Check the drains in the hatch, they are most likely clogged with debris if the water is just standing there and you're parked on level ground. The holes for the drains are in each back corner, can't miss them, and they connect to plastic hoses that direct the water out to the ground.

 

You might have some hidden water. My seals on my wing dry rotted and water enters through the hatch and pools up in the plastics. I never would have known until I lifted the hatch up and water dripped out.

 

If you checked the drain holes and they're clear, check all seals and weatherstripping. Doors, hatch, windows (including windshield and rear window), sunroof if you got one.

 

I found there's quite a bit of water in the door seals (on the door itself) on the bottom. it seems to be an unending amount coming out of the little hole even if I keep squeezing and squeezing. I am guessing it's not supposed to be holding water like this. the plastic cover underneath the hatch also seems to be wet.

 

no its IN the hatch frame. you open it and you can hear water running around, which is like my first miata, sounded like you were driving a bath tub

 

That's weird... We talking FC or FD hatch frame? If it's an FD, I can see how water might get in via one of the holes for the OEM spoiler on the hatch, if any of the seals there failed. Not so sure how water gets in on an FC hatch frame - unless you have the OEM rear wiper/washer, the washer nozzle mounts on the hatch frame, so maybe a compromised seal there?

 

After I wash my FD, water has ALWAYS dripped out around the hatch window seal, even when it was brand new in early '92. However, I've never had any symptoms of wetness or fogging inside the car..

 

oh good thinking, yes its an FC.

 

friend of mine had the condensation when his heater core leaked

 

i worked around the car inside and out in the sun and also wiped the windshield on the inside with glass cleaner (haven't done it in a while) and it seems that the condensation is not coming back. strange