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OK, I live in the pacific northwest and it has been raining big time. Everytime I get in my Croc the front window either is fogged or fogs instantly. There is no siginifcant water in my rubber mats. The a/c compressor is on, recirculation is off. My other cars (e.g. '98 M3) in the same conditions don't do this at all. Although hitting the front defrost climate control button clears the window in 10 seconds or so, this is something I have not experienced in my other vehiceles. Any thoughts?
 

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I'm in Moscow, colder but same air and rain as you. I haven't noticed any instant fogging in the Cayman yet (very few data points), but I do get it in the GTI every year around this time. I suspect a really good inside window cleaning might help.
 

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I have the same instant fogging on occasion where I live. What amazes me is I press the defogger button and instantly it clears my windshield. Just one push, for about a couple seconds, seems to do the trick and it fogs no more.
 

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I think it's just a quirk of the car. Moist air settles in the A/C ducts and upon startup gets pushed out before the A/C system has a chance to dehumidify, but as you said gets cleared up quickly.

I have also seen this more on cars with cabin filtration.....the filter sometimes holds some moisture in it. Does your M3 have this?

Try this,.....a couple minutes before shutting the car down put the A/C in recirc mode to really dry out the air and cabin filter in your car.....see if that helps the next time at startup.
 

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OK, I live in the pacific northwest and it has been raining big time. Everytime I get in my Croc the front window either is fogged or fogs instantly. There is no siginifcant water in my rubber mats. The a/c compressor is on, recirculation is off. My other cars (e.g. '98 M3) in the same conditions don't do this at all. Although hitting the front defrost climate control button clears the window in 10 seconds or so, this is something I have not experienced in my other vehiceles. Any thoughts?
to me the defroster is the worst out of the 20 cars that I have owned--a few of my cars never had the defroster on though
 

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Discussion Starter #7
Just some more info. So far temp has been above 3 degrees C--so that isn't the issue.

Yes my M3 (and the other cars I drive) all have cabin filters, and none of them do this.

I will try the recirc thing to get the cabin air relative humidity low and see if that helps.

I don't really want to bug the dealer with a non-issue, and if this is a quirk I can live with it--but, all things being equal, I'd like it gone.
 

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You know, I have been waiting almost a year for someone to ask this question. I live near DC and my windows fog up almost every day continuously. Even in the summer. AC on or off, circ on or off (I think). I keep having to push the DEFROST button until it gets too hot in the car and then 15 minutes later it fogs up again. I have never had that happen before in any other car. Not a complaint, I still love the car, but I am curious why it happens.
 

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You know, I have been waiting almost a year for someone to ask this question. I live near DC and my windows fog up almost every day continuously. Even in the summer. AC on or off, circ on or off (I think). I keep having to push the DEFROST button until it gets too hot in the car and then 15 minutes later it fogs up again. I have never had that happen before in any other car. Not a complaint, I still love the car, but I am curious why it happens.
In the summer, I suspect the condensation is on the outside. By default, the AC is blowing cold air out the defroster ducts. That makes the glass cold and our lovely DC humidity immediately condenses on the glass. I got around it by pushing the button that makes the cold air just come out of the dashboard ducts.

YMMV
 

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Are you sure on this? :)
Page 131 - 2006 Cayman S owner's manual:

"ECO – switching the air-conditioning
compressor on and off

The air conditioning compressor switches off
automatically at temperatures below approx.
37°F/3°C and cannot be switched on, even
manually.

Whenever outside temperatures exceed approx.
37°F/3°C, the air-conditioning compressor can be
switched on or off manually."



brad
 

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I have the same issue, most window would fog up pretty bad. My bimmer doesn't have this problem, but after you blast the vents a big, it goes away.
 

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OK, I live in the pacific northwest and it has been raining big time. Everytime I get in my Croc the front window either is fogged or fogs instantly. There is no siginifcant water in my rubber mats. The a/c compressor is on, recirculation is off. My other cars (e.g. '98 M3) in the same conditions don't do this at all. Although hitting the front defrost climate control button clears the window in 10 seconds or so, this is something I have not experienced in my other vehiceles. Any thoughts?
Don't feel alone. I live near Seattle, and have been experiencing the same fogging problem since I took delivery on my Cayman in October. I have never had the problem to this extent before on a car, including my 2003 Boxster S. I also still have the brake squeal at temp, during light braking. Maybe I can convince my wife this car is a lemon, and order a GT2. :D
 

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This fogging issue is not new to the Cayman (my prior 986 and 996 had the same issues - although the 986 was worst than the 996). Some ideas to help/solve the fogging problem:

1. Have the AC compressor (or at least the econ button no lite up) whenever you are trying to defog the windows.

2. Adjust the temperature when using the "defrost" button with the AC compressor on (econ button not lite) to prevent the bake out scenario (note: too cold of air under certain environmental conditions will result in condensation on the outside of the windshield which is more of a pain (IMO) than fogging in the interior).

3. Dictating the air flow to the windshield and using the AC compressor and the temperature control can solve the fogging issues (note the too cold of air scenario in #2 though).

4. Thoroughly clean the interior windows with a good glass cleaner. I have noticed that as the time between inside glass cleaning goes, the "fogging" issue increases dramatically. Granted freshly cleaned windows will not solve the problem but in combination with the foregoing makes it a none issue.

My experience with this fogging issue in both the 986 and 996 is the reason I did not want the Auto climate control in the CS, as I found it is much more easily controlled with manual settings than using the auto settings.
 

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With the Hot Hazy Humid weather we've been having here lately I've been dealing with the condensation on the outside issue. I tried turning off the air to the windshield with not much luck. I just have to run the wiper every minute or so to clean off the condensed water. With the sport seats I'm down low too, so it's right in my line of sight.
 

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With the Hot Hazy Humid weather we've been having here lately I've been dealing with the condensation on the outside issue. I tried turning off the air to the windshield with not much luck. I just have to run the wiper every minute or so to clean off the condensed water. With the sport seats I'm down low too, so it's right in my line of sight.
Once the condensation starts on the outside it takes a long time of no AC on the windshield stop forming, and you are correct the only solution is continuing to use the wipers. However, if you adjust your vent settings prior to the condensation forming you should not have an issue. The settings of the Auto climate or the Max AC have too much cold air onto the windshield and eventually you will get the outside condensation. I usually use the max AC to get the swelter out then turn off the windshield setting prior to the formation of the condensation to avoid this issue.
 

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In the summer, I suspect the condensation is on the outside. By default, the AC is blowing cold air out the defroster ducts. That makes the glass cold and our lovely DC humidity immediately condenses on the glass. I got around it by pushing the button that makes the cold air just come out of the dashboard ducts.

YMMV
I agree. Here in Houston, TX, the outside humidity in the early morning is the problem. Cool air holds less moisture, so the cool air from your AC causes condensation on the OUTSIDE of the windshield. After trying nearly every combination of ducts/AC settings, the only thing that works is to set the fan on its lowest setting, ie "one bar." Set the AC temp as low as it goes. This will keep the interior pleasantly cool, yet not blow cold air on the winshield at a high enough rate to cause outside condensation. By the time the sun warms things up, the air can hold more moisture, and you can crank your fan up as high as you like, with not condensation. BTW if the moisture is forming on the inside, you simply need to dry the air out with standard AC settings.
 

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My rear (hatch) window fogs up all the time regardless of hot or cold weather. I have reasoned it might be that I drive a lot with the windows down and that dust naturally collects on the inside of the window (from ram air effect w/windows down) providing a better substrate for condensate to collect. The rear defrost action doesn't do a great job a keeping it clear either. Oh well, small price to pay for such a great car.
 

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I agree. Here in Houston, TX, the outside humidity in the early morning is the problem. Cool air holds less moisture, so the cool air from your AC causes condensation on the OUTSIDE of the windshield.
I am jumping in late to the thread, but strictly speaking, the issue is that the surface temperature of the window is lower than the dewpoint of the outside air. Its exactly the same principle as taking a cold beer from the fridge.

You need to prevent the surface temp of the windshield from dropping below the outside dewpoint, or warm it up if it already is too cold.

Running the AC full bore and having the windshield vents on is not going to help at all, and in fact make it worse. You would want to adjust the temperature slider to warm up the air leaving the defusers. My comment is based on operation of the manual AC system. You can probably just nudge it over a few clicks so that the air is warmed slightly to have a positive effect, but if the window is really cold relative to the dewpoint, more heat will be required.

Brian
 

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I am jumping in late to the thread, but strictly speaking, the issue is that the surface temperature of the window is lower than the dewpoint of the outside air. Its exactly the same principle as taking a cold beer from the fridge.

You need to prevent the surface temp of the windshield from dropping below the outside dewpoint, or warm it up if it already is too cold.

Running the AC full bore and having the windshield vents on is not going to help at all, and in fact make it worse. You would want to adjust the temperature slider to warm up the air leaving the defusers. My comment is based on operation of the manual AC system. You can probably just nudge it over a few clicks so that the air is warmed slightly to have a positive effect, but if the window is really cold relative to the dewpoint, more heat will be required.

Brian
You're right about keeping the air warmer in the car. I found unfortunately that to prevent outside condensation I had to keep the interior air a little too warm. It was uncomfortable, especially when trying to cool a warm vehicle after startup. I found that setting the blower on its' lowest setting and temp on coldest, you can get comfortable in about a minute if you aim the dash vents towards you. The trickle air flow onto the inside of the windshield doesn't cool the glass quickly enough to allow outside condensation. Glass luckily is a pretty good thermal insulator. Once I figured this out, I haven't had a problem since. The alternatives that I know of are to periodically blast hot air to clear things up, or run your wipers or keep the interior (uncomfortably) warm. Hope this helps.
 
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