Infiniti G37 interior condensation

When it rains or snows, my '08 G37S coupe gets condensation above the interior vents on the dashboard and rear deck–nowhere else. No leaks evident anywhere. Any ideas about what’s wrong and how to make it stop?

Does the condensation only happen until the car has warmed up? If so, that’s pretty normal. You track snow and rain into the car on your shoes, and then you breathe, which compounds the problem. Once the cabin warms up the condensation should go away.

It happens before I get in the car, only in limited area over the dash and rear deck, but quite a bit of moisture–have to run the defogger and defroster quite a while to get rid of it. I’ve never seen this phenomenon in any other vehicle and only the past few months in my G37.

That part of the glass is going to be warmer than the rest of the glass after you turn the car off because it’s what gets hit directly by the defrost vents. As it cools moisture will condense if atmospheric conditions are right. I’m not overly surprised you haven’t seen it before. If your winter has been anything like mine, we’ve had weather conditions not seen in 30+ years.

Best advice is to knock the snow off your shoes before you get in, and dump out the water if it’s pooling in your all-weather floormats (and if you don’t have them, get them, because otherwise the carpet absorbs all that water and then evaporates it later).

As long as you aren’t smelling coolant, which would indicate a heater core leak, then it’s probably not anything to worry about. That it’s fogging up on the back window tells me it’s probably not a heater leak.

One thing to do for interior moisture is to absorb it.
If you’ve ever encountered those little packets of silica gel in products you buy…you can use those.
For my 06 Escape hybrid I used sticks of school chalk.
Place them anywhere and out of sight like door pockets, glove box, console, under seats and they will absorb the excess moisture.