Cobalt windshield ices up on the inside

[tvanduzee]

I have a 2007 Cobalt LS
The windshield ices up on the inside. However, it does not ice up until I turn on the defrost. Until I turn it on, the windshield is clear.
I have also found that sometimes snow will blow in through the defrost too.
I don't think its moisture in the air because it would be iced up when I first get into the car. This is actually a hazard because it ices while driving.

I do live in a cold climate (winter is normally between -25 to -45 degrees C. Lots of snow.

This only began happening a few weeks ago. Until then it was never an issue and I've had the car for 3 yrs.

Any suggestions?

Thanks
Terry

 

[Newbian]

You will probably get more help if a mod moves this to the garage area.

 

[Theb]

From the title I thought the windshield was made of cobalt, anyway.

Have you tried turning on recirc so you don't pull any air from outside?

 

[IronWing]

Leaky heater core?

 

[PowerEngineer]

Leaky heater core?

My first thought as well. If there's a sweet smell, it suggests antifreeze.

 

[twinrider1]

...winter is normally between -25 to -45 degrees C.

Any suggestions?

Just one. -25c, holy crap.


Seriously, move. Until then, I agree with the coolant leak. Try leaving a window open a little when you park it for the night; see if changes anything.

 

[Jimzz]

Does your AC system work?

The defroster in a car turns the AC on with the heat. It does this and performs like a dehumidifier. If the AC system does not work then it will blow wet air up not dry air.

Also check the drain for the HVAC system. If its clogged then the air will remain wet as well.

 

[SparkyJJO]

Does your AC system work?

The defroster in a car turns the AC on with the heat. It does this and performs like a dehumidifier. If the AC system does not work then it will blow wet air up not dry air.

Also check the drain for the HVAC system. If its clogged then the air will remain wet as well.

Not always. The AC in my first two cars didn't work but defrosters were fine once the car was warmed up. My current one only uses the AC to dry the air on the lower temp settings on the defrost. Full (or near full) heat setting only uses hot air off the heater core as that is pretty dry air at that point. The AC system will freeze itself if it tries to run in cold temps. There is a switch that won't let it run when the outside temp is below a certain point to prevent freeze up.

If you turn your defrost on full blast when the car is still cold it can create more fog on the inside of the window to start with sometimes. In cold enough temps (-25C yikes) it can freeze pretty fast. I've had that happen before. If the car is warmed up when hitting defrost it should blow hot air and that shouldn't freeze up. If it is blowing colder air on defrost regardless of temp setting, but regular heat works, there could be an air door actuator issue not letting hot air get to the defrost vents.

 

[Pacfanweb]

My first thought as well. If there's a sweet smell, it suggests antifreeze.

Antifreeze doesn't ice up.

 

[Pacfanweb]

They had a problem with water getting into the HVAC case.

Here's what the TSB says to do:
#05-01-38-016B

Condition
Some customers may comment on water leaking on the front passenger side floor of the vehicle. This leak would occur under high ambient temperatures and high humidity situations when the customer has the air conditioning on high. Leaks will appear to be coming from the HVAC module where the heater core cover and lower case come together. Also, some customers may comment on water droplets blowing out of the vents when the A/C is on high.

Cause
This condition may be due to water condensing in the HVAC case that adheres to the upper surface in the tongue and groove area of the lower case and then leaking out.

Correction
Install the foam gasket between the heater core cover and the lower HVAC case at the location of the leak using the procedure listed below.

Remove the right side insulator/closeout panel retainers and the panel, if equipped.



Remove the 5 screws (1) (HHR) or break the 4 welds (2) (Cobalt/Pursuit) from the heater core cover at the specified locations.



Carefully pry apart the heater core cover and the lower HVAC case to achieve a 12.7 mm (0.5 in) gap.






Install the foam gasket, P/N 15878211, using a flat rigid tool (feeler gauge shown) into the sump area (1) of the heater core cover.
Reassemble the case using the 5 screws that were removed (HHR) or with new screws (Cobalt/Pursuit), P/N 11609829. For Cobalt/Pursuit, add an additional screw (2) at rear of sump area.
Install the right side insulator/closeout panel and retainers, if equipped.




Other things to check: First, the A/C drain to make sure it's not just stopped up. That'd be the easiest thing.

Other: Make sure the windshield weatherstrip isn't loose and allowing water to get into the cabin air filter housing, which will fill up the heater case.

 

[dawp]

From the title I thought the windshield was made of cobalt, anyway.

Have you tried turning on recirc so you don't pull any air from outside?

every owners manual I've read said the opposite because recirc will have moisture in the air just from breathing. in cold weather the air from outside will be drier simply because cold air can't hold as much humidity as warm air. that's why you get frost or dew when the temp drops.

 

[mmntech]

Sounds like you've got a problem either with your thermostat or heater core. When the car is warmed up, is hot air coming out the other vents? That might narrow things down a bit.

 

[Pacfanweb]

every owners manual I've read said the opposite because recirc will have moisture in the air just from breathing. in cold weather the air from outside will be drier simply because cold air can't hold as much humidity as warm air. that's why you get frost or dew when the temp drops.

Recirc and defrost. Defrost runs the compressor, which will remove humidity, and recirc to keep the same air circulating so no new humidity gets in.

In nearly every car nowadays, the only positions that the compressor does NOT run is Floor and Vent. It is automatically on in every other position.

Could be some exceptions, but not many.

Recirc, or "Max" is optional, except obviously on "Max A/C".

 

[LTC8K6]

Recirc is never total, iirc. There is always some fresh outside air in the flow.

 

[Pacfanweb]

Recirc is never total, iirc. There is always some fresh outside air in the flow.

Depends on the car, I guess. On all cars I've even seen, there's a door, or 'wall' in some cases, that either blocks off the opening for the fan to suck air from the inside or the outside. And it blocks it off "completely".....and by the quotation marks, I mean, as much as a plastic door that at most has some sort of foam seal on it.

It's not going to be but so "airtight", so I'm sure some air might slip by it, but I've never seen one that only blocks off the outside air partially...in other words, designed to always let some in.

I've watched a many a one open and close while looking for water leaks, too....but I surely haven't seen them all, so maybe some don't shut all the way...but I've watched them from inside and outside, and never seen one that didn't look like that it was least INTENDED to block off all the air. Whether they're all successful, depends on the design.

I know on my Suburban, if I have the fan off and switch on anything besides Max, and the Max button off and drive down the road, I get airflow. Switch it to Max, airflow stops.
Some might be different, I guess.

 

[LTC8K6]

I believe it is not full recirc in case of an exhaust leak and to prevent stagnant/low oxygen air from building up. Both of which will put you to sleep.

Recirc uses about 10% fresh air, just from memory.

 

[AMCRambler]

Pulling snow through the vents sounds like the cabin air filter may have a hole in it. Many mice chewed it up? Would be worth a look.