window fogging in humid air
#1
window fogging in humid air
It's hot and humid lately and with the A/C running I get a damp mist on the outside of the windshield running about 5 inches up from the base. The wiper clears it away but I get this on no other car. Is this normal?
#3
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Yes, that is normal. If you want to avoid the lower windshield fogging issue, take the A/C off the "auto" setting and direct more of the air through the dashboard vents. This will minimize the amount of air exiting the windshield vents and eliminate most or all of the fogging on humid days.
You can do this by hitting the middle button on the right side of the A/C control panel. The graphic on this button looks like the "dual vents" on the center console.
You can do this by hitting the middle button on the right side of the A/C control panel. The graphic on this button looks like the "dual vents" on the center console.
#4
Race Car
That will happen on any surface depending on the dew point when running air conditioning. You'll notice it on your house windows at times if you run your cooling down to too low of a temperature.
#6
Burning Brakes
Same Problem
Originally Posted by gillie
It's hot and humid lately and with the A/C running I get a damp mist on the outside of the windshield running about 5 inches up from the base. The wiper clears it away but I get this on no other car. Is this normal?
#7
Normal...the stupid "Auto" setting sends too much cool air to the window vents. As stated above, use the vent selection buttons for the dash and/or floor and the problem will be solved. Once the moisture appears it taks a little time to go away after you switch the vents. I have gotten in the habit of not using the Auto button in the summer.
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#8
Drifting
When I returned my 2001 to the factory for shipment to the US I complained of this problem and the rep acknowledged and agreed to look into it. I didn't realize that nothing had been done until about 8PM driving into Birmingham AL after taking delivery at POE. It was July, hot and humid evening and we had just driven through a light rainshower.
At first I thought the headlights were failing.
But yes, this is a definite design flaw of which the factory is fully aware and refuses to address.
Funny thing is that VW has addressed it on their version of the Cayenne(firmware update) but Porsche still refuses to acknowledge that it's a problem, a design flaw, a potentially HAZARDOUS one at that.
Some details...
Apparently no airflow is routed to the windshield until the cabin is cooled too, or very near your temperature setpoint. Once that happens the apparent level of cooling to the cabin changes dramatically. Part of my complaint in Germany to the factory rep was that in order to be comfortable I had to keep "fiddling" with the setpoint.
The windshield is not a very good insulator, obviously, and so the cooling effect of the airflow striking it is lost, mostly, to cool the great outdoors.
It is not humanly possible to judge the level of humidity at any given time, especially isolated as we are inside the cabin. So it's a very good idea, most especially at night, to be super diligent about preventing exterior fogging on the windshield by selecting only dash and/or footwell cooling airflow.
At first I thought the headlights were failing.
But yes, this is a definite design flaw of which the factory is fully aware and refuses to address.
Funny thing is that VW has addressed it on their version of the Cayenne(firmware update) but Porsche still refuses to acknowledge that it's a problem, a design flaw, a potentially HAZARDOUS one at that.
Some details...
Apparently no airflow is routed to the windshield until the cabin is cooled too, or very near your temperature setpoint. Once that happens the apparent level of cooling to the cabin changes dramatically. Part of my complaint in Germany to the factory rep was that in order to be comfortable I had to keep "fiddling" with the setpoint.
The windshield is not a very good insulator, obviously, and so the cooling effect of the airflow striking it is lost, mostly, to cool the great outdoors.
It is not humanly possible to judge the level of humidity at any given time, especially isolated as we are inside the cabin. So it's a very good idea, most especially at night, to be super diligent about preventing exterior fogging on the windshield by selecting only dash and/or footwell cooling airflow.
#10
Rennlist Member
I have been messing with this on my new to me 02. On mine changing the vents does not stop the foging driving around at slow speeds.. But getting on the freeway does. More air flow somewhere I guess?
#12
Originally Posted by mario911c4s
It bothers me just as much as my ratteling noise out of my exhaust!
#13
Drifting
Reply to Steve Cole:
More than likely "At speed" on the highway more cabin airflow is being "wicked" out the passenger cabin via the two exhauster ports at the rear. Moving slowly the blower exhaust/output (windshield defrost/defog/demist) velocity designates flow direction directly to the windshield. Then at highway speeds with a higher exhauster flow rate the outflow path deviates toward the rear.
Just a guess.
But it sounds just a bit like you might be talking about interior windshield fogging....???
More than likely "At speed" on the highway more cabin airflow is being "wicked" out the passenger cabin via the two exhauster ports at the rear. Moving slowly the blower exhaust/output (windshield defrost/defog/demist) velocity designates flow direction directly to the windshield. Then at highway speeds with a higher exhauster flow rate the outflow path deviates toward the rear.
Just a guess.
But it sounds just a bit like you might be talking about interior windshield fogging....???
#15
Burning Brakes
Inside - you sure?
Originally Posted by Steven Cole
Yes, mine is on the inside. Is everyone else's not?
Mine is also less of a problem when I hit the freeway, but that is because the air flows too quickly to cool to the dew point.
Moisture on the inside suggests perhaps a leaky heater, but that doesn't seem like it would be in use in the summer and you would smell the coolant.