Windshield condensation...
08-28-2004, 01:21 PM
#1
Drifting
Thread Starter
Windshield condensation...
If you are experiencing this problem, of which Porsche is very well aware, there are postings on a forum unique to the VW Toureg that indicates VW has released a firmware update to solve it.
I first reported the problem with my 01 C4 in May of 01 as I returned it to the factory for shipment to the US. To date Porsche has refused to address the issue even though the shops seem to be fully aware of it and the hazardous driving potential therefrom.
The Bellevue Barrier service manager and I just recently verified that the 04 996 models still have this problem.
I first reported the problem with my 01 C4 in May of 01 as I returned it to the factory for shipment to the US. To date Porsche has refused to address the issue even though the shops seem to be fully aware of it and the hazardous driving potential therefrom.
The Bellevue Barrier service manager and I just recently verified that the 04 996 models still have this problem.
Last edited by wwest; 10-27-2004 at 05:10 PM.
08-28-2004, 01:38 PM
#2
Rennlist Member
So, what is the problem?
08-28-2004, 06:00 PM
#4
Drifting
Thread Starter
The Porsche (Bosch??) climate control system appears to have a fairly serious design flaw. When the A/C is on and the system is in cooling mode and once the cabin has acclimated to something near the temperature setpoint the system will automatically begin to route a significant portion of the CHILLED airflow to the interoir surface of the windshield via the defrost/defog/demist outlet ducts.
Once the windshield is chilled to the dewpoint of the outside atmosphere condensation will begin to form on the OUTSIDE of the windshield. This can happen reasonably suddenly and at night it is difficult to notice before your forward vision is severely obscured.
I recently did a search on google for "windshield condensation" and came across a Touareg forum wherein many owners are having this problem and some are reporting that VW has a fix available that involves reprogramming the climate control ECU.
I posted the note here because I assumed that since my C4 has the problem and the Touareg does then it is highly likely that the Cayenne does also. Actually if you browse the later air-cooled 911 forums you will discover some complaints of this nature over there also.
Once the windshield is chilled to the dewpoint of the outside atmosphere condensation will begin to form on the OUTSIDE of the windshield. This can happen reasonably suddenly and at night it is difficult to notice before your forward vision is severely obscured.
I recently did a search on google for "windshield condensation" and came across a Touareg forum wherein many owners are having this problem and some are reporting that VW has a fix available that involves reprogramming the climate control ECU.
I posted the note here because I assumed that since my C4 has the problem and the Touareg does then it is highly likely that the Cayenne does also. Actually if you browse the later air-cooled 911 forums you will discover some complaints of this nature over there also.
08-28-2004, 06:52 PM
#5
Instructor
I have noticed it as well, but thought that I simply did not know the proper adjustments. Mostly condensation on the lower windshield when the AC is on. Keep us updated.
08-29-2004, 12:14 AM
#7
Drifting
Thread Starter
Set the temp to 74F.........
It doesn't help, once the system cools the cabin down to ~76F, the system starts distributing the CHILLED A/C airflow from the dash AND the defrost/defog/demist windshield ducts. I have used two ways to defeat this aspect...
One is to manuall select dash outlets and/or dash and footwell outlets. However, using the footwell outlets in recirc during cooling operations is not a good idea.
The second method I more often use also results in improved fuel economy. Run the system on max cool and then use the blower speed to regulate your comfort level. At the max cool setting the system NEVER routes the aurflow to the windshield.
It doesn't help, once the system cools the cabin down to ~76F, the system starts distributing the CHILLED A/C airflow from the dash AND the defrost/defog/demist windshield ducts. I have used two ways to defeat this aspect...
One is to manuall select dash outlets and/or dash and footwell outlets. However, using the footwell outlets in recirc during cooling operations is not a good idea.
The second method I more often use also results in improved fuel economy. Run the system on max cool and then use the blower speed to regulate your comfort level. At the max cool setting the system NEVER routes the aurflow to the windshield.
Trending Topics
08-29-2004, 11:23 AM
#8
Moderator !x4
Strange this normally occurs in hotter climates than you are in. There was a very technical description of why this happens last year, you might try a search. It occurs mainly on the passenger side as I recall, unlike the Mercedes which would "flash fog" the whole windscreen and force me to use defost and wipers.
In my case leaving the setting to auto and raising temp to 74 both sides stops this from ever happening.
In my case leaving the setting to auto and raising temp to 74 both sides stops this from ever happening.
09-08-2004, 01:32 PM
#9
Drifting
Thread Starter
Correction...
Inadvertantly discovered that a max cool setting does not allow defrost/defog/demist to operate properly, gets only COLD airflow. But a setting of 1 degree above max cool, 64F in my case(01 C4), seems to work fine, HOT airflow to the windshield in defrost/defog/demist mode.
And 64F is probably still low enough that it's never reached and so there would likely be little danger of the system automatically switching to partial windshield cooling and the resultant potential for windshield condensation.
Inadvertantly discovered that a max cool setting does not allow defrost/defog/demist to operate properly, gets only COLD airflow. But a setting of 1 degree above max cool, 64F in my case(01 C4), seems to work fine, HOT airflow to the windshield in defrost/defog/demist mode.
And 64F is probably still low enough that it's never reached and so there would likely be little danger of the system automatically switching to partial windshield cooling and the resultant potential for windshield condensation.
09-08-2004, 08:56 PM
#12
Drifting
Thread Starter
Eskimo blood......
No, I adjust the blower speed to attain my comfort level. But in a way you're right, the airflow does come out of the dash vents quite cold, but a low(est) blower speed moderates the overall cooling level very well.
No, I adjust the blower speed to attain my comfort level. But in a way you're right, the airflow does come out of the dash vents quite cold, but a low(est) blower speed moderates the overall cooling level very well.
