So much moisture...
11-26-2006, 11:30 AM
#1
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So much moisture...
I took the 996 out to the movies after it sitting for a few days. Drove it 15 minutes to the theatre, got out and it sat for about 2.5 hours. Got back and the whole car was soooooo fogged up on the inside. It almost looked like someone had taken a shower inside the car with all the doors closed? Is this normal? I live in Boston, and it was about 50ish yesterday during the day and then 30's at night. Why would there be so much moisture inside the car? Thanks in advance.
11-26-2006, 12:20 PM
#2
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I have the same issue with my car. It is kind of annoying when you get back in and have to wait for it to warm up so it will defog. Hopefully someone can chime in here...
11-26-2006, 01:58 PM
#3
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Funny, I've experienced the problem in Seattle. 
I've never found the root cause, but it does occur if I park at the airport for a few days during the rainy season and come back at night when it's cold. This doesn't happen while the car sits in my garage for a week. But, I keep the windows rolled down when it's parked in the garage so I think the insides get vented better.
My guess would that in driving your car, you expell humidity into the cabin and it's trapped. Lower temperatures cause the condensation or fog you speak of. If it's a real bother, you might want to try a box of Damp-Rid (with the non spill tyvex cover) in the foot well of the rear seat. Should help absorb excess moisture. It's heavy, so it won't flip over, and with a strip of velcro, it won't move around on the carpet either.
I use to do this for an older vehicle of mine which did not have AC. Try getting rid of condensation without AC sometime...
Thanks,
Peter
I've never found the root cause, but it does occur if I park at the airport for a few days during the rainy season and come back at night when it's cold. This doesn't happen while the car sits in my garage for a week. But, I keep the windows rolled down when it's parked in the garage so I think the insides get vented better.
My guess would that in driving your car, you expell humidity into the cabin and it's trapped. Lower temperatures cause the condensation or fog you speak of. If it's a real bother, you might want to try a box of Damp-Rid (with the non spill tyvex cover) in the foot well of the rear seat. Should help absorb excess moisture. It's heavy, so it won't flip over, and with a strip of velcro, it won't move around on the carpet either.
I use to do this for an older vehicle of mine which did not have AC. Try getting rid of condensation without AC sometime...
Thanks,
Peter
11-26-2006, 02:04 PM
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Do you turn on the heat way up when you are driving in the car?
That would cause a huge difference in temp between the interior and exterior, thus condensation.
I'm just guessing...not a genius in this area.
When it's cold outside and I have the heater on in my house, the windows sweat and drip on the insides too.
That would cause a huge difference in temp between the interior and exterior, thus condensation.
I'm just guessing...not a genius in this area.
When it's cold outside and I have the heater on in my house, the windows sweat and drip on the insides too.
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11-26-2006, 05:33 PM
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As some others have said...
The windows in my car get foggy too, sometimes. It depends a lot on the weather and also the people inside and whether the air conditioning/heater is running.
Car windows fog up when water condenses on them. This can happen both on the inside of the window and on the outside.
Water will condense on a surface if the temperature of the surface is below the dew point of the air next to that surface. So you need warm, humid air next to a cooler surface to fog up.
Often, the air in the car will be warmer than the air outside the car (this happens in winter here). Moisture will condense on the inside of the windows if the outside air is cooler than the dew point inside the car. This happened to me a lot when driving through a thunderstorm caused by an incoming cold front. In this case, running both the air conditioner, the heater, and the vents for defrosting the front window worked very effectively. The air conditioner dehumidifies air because water condenses inside it when the air goes past the cold tubes with the refrigerant inside. Heating it up way past its dew point makes it feel dry, and it is dry -- it’ll help evaporate any condensation that’s on the windshield -- and even more quickly the hotter it is because heat is needed to cause the liquid water to change phase to a gas.
Hope this helps
The windows in my car get foggy too, sometimes. It depends a lot on the weather and also the people inside and whether the air conditioning/heater is running.
Car windows fog up when water condenses on them. This can happen both on the inside of the window and on the outside.
Water will condense on a surface if the temperature of the surface is below the dew point of the air next to that surface. So you need warm, humid air next to a cooler surface to fog up.
Often, the air in the car will be warmer than the air outside the car (this happens in winter here). Moisture will condense on the inside of the windows if the outside air is cooler than the dew point inside the car. This happened to me a lot when driving through a thunderstorm caused by an incoming cold front. In this case, running both the air conditioner, the heater, and the vents for defrosting the front window worked very effectively. The air conditioner dehumidifies air because water condenses inside it when the air goes past the cold tubes with the refrigerant inside. Heating it up way past its dew point makes it feel dry, and it is dry -- it’ll help evaporate any condensation that’s on the windshield -- and even more quickly the hotter it is because heat is needed to cause the liquid water to change phase to a gas.
Hope this helps
11-26-2006, 06:12 PM
#10
Drifting
Guess what....?
I can tell you the answer, the EXACT answer...!
I had Squires Autowerkes (Bellevue WA) install a small toggle switch inside the center glovebox. I use this switch to used to open the A/C compressor's electromagnetic clutch circuit at any and all times the OAT is predominantly below the point wherein actual cooling is needed.
The problem is:
When the outside atmosphere is "coolish" the only use of the A/C is to dehumidify the FRESH airflow entering the passenger cabin. The efficiency, ne, possibility, of success is totally dependent upon local climatic conditions, a total WILD CARD.
In general, the lower the OAT, the lower will be the moisture content in the local atmosphere. Currently ALL manufacturers seem to be working diligently to increase the probability/possibility of the A/C being efficient in the process of dehumidifying the fresh incoming airflow.
In order to dehumidify the incoming fresh airflow the A/C system must be capable of reducing that airflow's temperature down to its dewpoint, the point at which airborne moisture begins to condense onto the ~10,000 square inches of CHILLED, 35F, evaporator vane surfaces. In order to achieve the highest probability of dehumidification the blower speed must be kept at its LOWEST, therefore these passenger cabins are very well sealed to retrict the outflow of the previously conditioned passenger cabin atmosphere. Since the cooling evaporator's surface temperature can NEVER decline to freezing the only way to increse its efficiency is to add cooling surface area. What, this is a Porsche 996 and there simply isn't enough room for a cooling evaporator with 10,000 square inches of surface area...???
WRONG..!
Think SPONGE.
Modern day A/C evaporator cooling vane surfaces are so tightly "woven" that a slight increase in the viscosity of the condensate will result in dropletts large enough to block all airflow at lower blower speeds.
So, when you park your Porsche, or Lexus, or..., there will be about 3 quarts of condensate remaining as a thin film on those 10,000 square inches of evaporator vane surface area due to previous A/C dehumidification functionality. Surprised when you come back 3 hours (even as much as three days) later having parked it out in the cold and now ALL of the interior window/windshield surfaces are coated with a think layer of condensate...??
Not I...
Go to airsept.com and read up on their EED, Electronic Evaporator Dryer, as a possible solution.
I can tell you the answer, the EXACT answer...!
I had Squires Autowerkes (Bellevue WA) install a small toggle switch inside the center glovebox. I use this switch to used to open the A/C compressor's electromagnetic clutch circuit at any and all times the OAT is predominantly below the point wherein actual cooling is needed.
The problem is:
When the outside atmosphere is "coolish" the only use of the A/C is to dehumidify the FRESH airflow entering the passenger cabin. The efficiency, ne, possibility, of success is totally dependent upon local climatic conditions, a total WILD CARD.
In general, the lower the OAT, the lower will be the moisture content in the local atmosphere. Currently ALL manufacturers seem to be working diligently to increase the probability/possibility of the A/C being efficient in the process of dehumidifying the fresh incoming airflow.
In order to dehumidify the incoming fresh airflow the A/C system must be capable of reducing that airflow's temperature down to its dewpoint, the point at which airborne moisture begins to condense onto the ~10,000 square inches of CHILLED, 35F, evaporator vane surfaces. In order to achieve the highest probability of dehumidification the blower speed must be kept at its LOWEST, therefore these passenger cabins are very well sealed to retrict the outflow of the previously conditioned passenger cabin atmosphere. Since the cooling evaporator's surface temperature can NEVER decline to freezing the only way to increse its efficiency is to add cooling surface area. What, this is a Porsche 996 and there simply isn't enough room for a cooling evaporator with 10,000 square inches of surface area...???
WRONG..!
Think SPONGE.
Modern day A/C evaporator cooling vane surfaces are so tightly "woven" that a slight increase in the viscosity of the condensate will result in dropletts large enough to block all airflow at lower blower speeds.
So, when you park your Porsche, or Lexus, or..., there will be about 3 quarts of condensate remaining as a thin film on those 10,000 square inches of evaporator vane surface area due to previous A/C dehumidification functionality. Surprised when you come back 3 hours (even as much as three days) later having parked it out in the cold and now ALL of the interior window/windshield surfaces are coated with a think layer of condensate...??
Not I...
Go to airsept.com and read up on their EED, Electronic Evaporator Dryer, as a possible solution.
11-26-2006, 06:31 PM
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Originally Posted by wwest
Guess what....?
I can tell you the answer, the EXACT answer...!
I had Squires Autowerkes (Bellevue WA) install a small toggle switch inside the center glovebox. I use this switch to used to open the A/C compressor's electromagnetic clutch circuit at any and all times the OAT is predominantly below the point wherein actual cooling is needed.
The problem is:
When the outside atmosphere is "coolish" the only use of the A/C is to dehumidify the FRESH airflow entering the passenger cabin. The efficiency, ne, possibility, of success is totally dependent upon local climatic conditions, a total WILD CARD.
In general, the lower the OAT, the lower will be the moisture content in the local atmosphere. Currently ALL manufacturers seem to be working diligently to increase the probability/possibility of the A/C being efficient in the process of dehumidifying the fresh incoming airflow.
In order to dehumidify the incoming fresh airflow the A/C system must be capable of reducing that airflow's temperature down to its dewpoint, the point at which airborne moisture begins to condense onto the ~10,000 square inches of CHILLED, 35F, evaporator vane surfaces. In order to achieve the highest probability of dehumidification the blower speed must be kept at its LOWEST, therefore these passenger cabins are very well sealed to retrict the outflow of the previously conditioned passenger cabin atmosphere. Since the cooling evaporator's surface temperature can NEVER decline to freezing the only way to increse its efficiency is to add cooling surface area. What, this is a Porsche 996 and there simply isn't enough room for a cooling evaporator with 10,000 square inches of surface area...???
WRONG..!
Think SPONGE.
Modern day A/C evaporator cooling vane surfaces are so tightly "woven" that a slight increase in the viscosity of the condensate will result in dropletts large enough to block all airflow at lower blower speeds.
So, when you park your Porsche, or Lexus, or..., there will be about 3 quarts of condensate remaining as a thin film on those 10,000 square inches of evaporator vane surface area due to previous A/C dehumidification functionality. Surprised when you come back 3 hours (even as much as three days) later having parked it out in the cold and now ALL of the interior window/windshield surfaces are coated with a think layer of condensate...??
Not I...
Go to airsept.com and read up on their EED, Electronic Evaporator Dryer, as a possible solution.
I can tell you the answer, the EXACT answer...!
I had Squires Autowerkes (Bellevue WA) install a small toggle switch inside the center glovebox. I use this switch to used to open the A/C compressor's electromagnetic clutch circuit at any and all times the OAT is predominantly below the point wherein actual cooling is needed.
The problem is:
When the outside atmosphere is "coolish" the only use of the A/C is to dehumidify the FRESH airflow entering the passenger cabin. The efficiency, ne, possibility, of success is totally dependent upon local climatic conditions, a total WILD CARD.
In general, the lower the OAT, the lower will be the moisture content in the local atmosphere. Currently ALL manufacturers seem to be working diligently to increase the probability/possibility of the A/C being efficient in the process of dehumidifying the fresh incoming airflow.
In order to dehumidify the incoming fresh airflow the A/C system must be capable of reducing that airflow's temperature down to its dewpoint, the point at which airborne moisture begins to condense onto the ~10,000 square inches of CHILLED, 35F, evaporator vane surfaces. In order to achieve the highest probability of dehumidification the blower speed must be kept at its LOWEST, therefore these passenger cabins are very well sealed to retrict the outflow of the previously conditioned passenger cabin atmosphere. Since the cooling evaporator's surface temperature can NEVER decline to freezing the only way to increse its efficiency is to add cooling surface area. What, this is a Porsche 996 and there simply isn't enough room for a cooling evaporator with 10,000 square inches of surface area...???
WRONG..!
Think SPONGE.
Modern day A/C evaporator cooling vane surfaces are so tightly "woven" that a slight increase in the viscosity of the condensate will result in dropletts large enough to block all airflow at lower blower speeds.
So, when you park your Porsche, or Lexus, or..., there will be about 3 quarts of condensate remaining as a thin film on those 10,000 square inches of evaporator vane surface area due to previous A/C dehumidification functionality. Surprised when you come back 3 hours (even as much as three days) later having parked it out in the cold and now ALL of the interior window/windshield surfaces are coated with a think layer of condensate...??
Not I...
Go to airsept.com and read up on their EED, Electronic Evaporator Dryer, as a possible solution.
11-26-2006, 07:10 PM
#12
I have a diff moisture problem, it does not fog up, but whenever it rains the passenger window groans and squeaks as it (more) slowly raises or lowers??? I'm assuming a faulty rubber gasket, its fine when its dry.
11-27-2006, 05:26 AM
#13
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Originally Posted by galeriehughie
I have a diff moisture problem, it does not fog up, but whenever it rains the passenger window groans and squeaks as it (more) slowly raises or lowers??? I'm assuming a faulty rubber gasket, its fine when its dry.
1/. Through the fresh air vent which by German law must remain fully open when the car is stopped. It moves towards closed with forward speed, but never fully closes. This requirement is there because of the heat exchanger system used by Porsche for the heating of internal air.
2/. Through the window seals which wear with age and how often the window goes up and down.
Note: If you have a Cab also check the roof seals. Check the front and rear mats to see if they are damp.
Note: If you have a Targa check the sliding roof glass seals. There are also drains in the Targa roof assembly. Make sure they are not blocked.
To help overcome the water ingress issues Porsche installed drains in the fresh air vent system and in the doors. Unfortunately the fresh air vent drains often get blocked up and it is a mongrel of a job to unblock them.
The doors also have drains at the bottom, but these are blocked off by the lower door seal when the door is closed.
So what can you do? Get the 996 inside, open the doors and let them drain. I did a tech session in the USA a couple of years ago and showed the people that attended these issues. They were all quite surprised especially when they saw the water drip out of the passenger door drains. The driver's door is used all the time obviously, but the passenger door can remain unused for a long time.
A great way to check is to open the driver's and passenger's side door compartments and put in some tissues. Leave for a couple of hours and then pull them out. If they are wet and soggy you know there is standing water in the doors.
Another check for water in the doors is to clean and dry the windows completely. Then lower and raise them, if they come up wet you have water in the doors.
Moisture ingress via the air-conditioning system can add to the problem, but the moisture problem would be present from new. If you suspect the aircon is the cause of the water ingress there is one little trick you can do. Select the vents to full blow into the footwell (away from the windshield) and see if any water drips out of the vents. Another idea might be to run the climate control system in manual mode instead of auto. Inotherwords turn the aircon off if you suspect the aircon is causing the problem. I only run my aircon in my 996 when I want cooling. I never just let it be operating all the time. If you select defrost it will come on anyway (well it does in mine) if the correct OAT conditions are met.
If the problem is starting to occur after some years there is a water leak somewhere.
Please remember that this is a common 911 problem across all the models ncluding all those without aircon. Aircon is an option and whilst it became a standard dealer option in the USA it was not adopted worldwide. But the moisture problem as described above and in the first post is worldwide.
In winter I would have as thick ice on the inside of the window as on the outside on my 911 (964) C4 which failed all the test and checks mentioned above.
Ciao,
Adrian.
PS: All Porsches are mobile water traps. If you have ever owned a 924 or 944 you would know where the water collects as well.
