This winter I've been encountering something that has me a bit confused on my daily-driver Saturn- on a number of mornings when it's been cold enough to ice/frost the windshield of the car I've also had to deal with frost/ice on the INSIDE of the windshield. I've never had this problem before this year- and I don't like it one bit since ice scrapers (at least mine) aren't curved to handle the inside curvature of the glass and it takes a while for the engine to get hot enough for for the climate control to melt it.
Anyone encounter this before, and/or have any insight on why it's happening and how to stop it? Thanks!
Sounds like you're getting moisture inside the car, either from tracking it in on your feet or from a leak somewhere.
An old credit card works well for scraping the inside of the windshield, it's flexible enough to conform to the curves.
Close the windows at night 
Yep moisture gets inside car, condenses on inside of glass because it's colder outside, then freezes because the glass is freezing.
Does your ac work?
Turn it on and set to hot. This will turn on the evaporater which will work like a dehumidifier.
In the winter time, I make it a point to let the car air out whenever I know the weather is conducive to it.
Otherwise, the cars stay closed up all winter and it's hard for the moisture to evaporate. Particularly when they leak water in or you forget to roll the windows up before a rain/snow storm 
As I post this, my car is in the parking lot at work with the windows rolled down a few inches...it's sunny and 48 degrees today.
Clem
If you have cloth floor mats, bring them inside over night to dry, that will help. Provided you can separate them from the car
Oh, you just need one of them inside-the-car sprayers.
I'll try airing the car out a bit on the way home (with the heat cranked up), and empty everything out. I've never had any problems with it leaking or water getting in, but I'll feel around and see if it has developed a leak somewhere and there's moisture trapped I should find a way to get out. Thanks!
In reply to Ashyukun:
If you have a garage, park in there and leave the windows open.... If its above freezing.
N Sperlo wrote:
In reply to Ashyukun:
If you have a garage, park in there and leave the windows open.... If its above freezing.
That statement needs the qualifier, "that you have room in to park a car." Mine is full of parts from working on the $2013 El Camino's engine. I will probably open the windows up and let it air out tomorrow while I'm working in the yard/garage nearby- it's not going to be -warm- by any stretch, but high-40s is better than below freezing...
Do you have a sunroof? Your drains may be plugged allowing water into the car. (ask how I know) There are 4 hoses, 2 go to the trunk, and the other 2 are in the kick panels. There are little one way valve thingie's on the ends that get clogged up easily, just cut them off. A squirt of rtv or something will help keep the hose where it belongs.
Gearheadotaku wrote:
Do you have a sunroof? Your drains may be plugged allowing water into the car. (ask how I know) There are 4 hoses, 2 go to the trunk, and the other 2 are in the kick panels. There are little one way valve thingie's on the ends that get clogged up easily, just cut them off. A squirt of rtv or something will help keep the hose where it belongs.
No, no sunroof. I wanted one with a sunroof, but I didn't want to wait the time it would have taken to factory order one, so I ended up without that or a spoiler and with the stock CD player instead of the base AM/FM radio (since I planned to almost immediately upgrade to a better head unit). In retrospect, while the sun/moonroof would have been nice, it also would have been a lot more of a hassle as the car aged though...
worst I ever had this happen was in an Expedition that had been parked out an an airport through a snow/ice storm. And is was 10 below.
Make sure any vents at the cowl a draining well. Water/ice/snow trapped there is what gave me trouble that time.
Also, make sure you don't have your air recirculating - be sure you are drawing in fresh air to the heater
Ashyukun wrote:
I've also had to deal with frost/ice on the INSIDE of the windshield. I've never had this problem before
You've have never owned an air cooled Beetle in your life.....this would be "normal".
Duke
PowerDork
1/18/13 4:00 p.m.
Gearheadotaku wrote:
Do you have a sunroof? Your drains may be plugged allowing water into the car. (ask how I know) There are 4 hoses, 2 go to the trunk, and the other 2 are in the kick panels. There are little one way valve thingie's on the ends that get clogged up easily, just cut them off. A squirt of rtv or something will help keep the hose where it belongs.
Yep - same thing happened in my E46. Totally, completely waterlogged the foam of the back seat, to the point of damaging the leather. It was not immediately apparent at ALL that this was happening. Just fog that wouldn't go away inside, and occasional frost.
Datsun310Guy wrote: You've have never owned an air cooled Beetle in your life.....this would be "normal".
The good thing about Beetles is the windshield was flat, plus it was pretty close to the driver, so scraping with one hand while driving with the other was pretty easy. 
Streetwiseguy wrote:
alstevens wrote:
Also, make sure you don't have your air recirculating - be sure you are drawing in fresh air to the heater
This.
I was following a car on the highway a few nights ago. The insides of the windows were completely fogged up on the inside. I can only guess they drive like my mom with the air set to recirc. She never turns it to fresh air.. EVER
Drive with the windows down.
Best way to air one out that's got moisture buildup is to run the heater with the A/C on. The warm dry air will evaporate moisture which will then go out the condensate drain. That's why many cars turn the compressor on when the defrost is on, the dry air removes moisture from the windows quickly.
