Foggy Windows

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?

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.

The A/C, (and therefore, it's dehumidifying action) doesn't function below 3c if that's any help.

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.

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.

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

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.

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

Are you sure on this?

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.

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.

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.

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.

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.

This doesn't help, but I've had no fogging issues with my car at all.

Ah yea, its the season again. I almost forgot about that issue until I had to starting fighting the fogging (and condensing) windows again this year....

FWIW, my CS does this. But so did my 2003 Boxster S. It's just something about the way Porsche designed the ventilation system.

I've only owned my '06 CS for a month, but noticed that once while coming home from a long road trip (6 hours each way) right after I bought the car, under full throttle and approaching 100 mph with the a/c on, the windshield fogged up on the lower right side. Was not a huge patch of fogging, but made me wonder. I probably should have turned off the compressor anyway, for accelerating but it was only for a few seconds before I let off the gas and coasted to a slower speed. The a/c works perfectly but I am curious why the fogging under heavy load? Has not done it again.