forum.audiv8.com Foren English Audi V8 Forum ClimateControl Blows Moisty Air

Hi!

Can anyone help me with this?

V8 3,6 from 1989 (Gletscherblau), My climatecontrol blows moisty air when temperatures outside show colder than +5 degrees Celsius.
All windows become full of water on the inside, and defroster blows even more moist.

Climatecontrol always on "AUTO" and 22 degrees celsius.
When I enter the garage (about +10 degrees Celsius) Climate control starts blowing cold in just a couple of minutes and it takes away all moist. As soon as i drive outdoors(+4 degrees today) in a couple of minutes it starts to blow moisty air again:(((

I have bought the car for 2 years ago and last winter I didn`t experienced these problems.
My climatecontrol unit shows less temperature than it is outside, so for example if the temperature outside is +20 degrees celsius, than my unit will show only +15 degrees. It was like this since I have bought the car, and the inside climate was good all the way, summer and winter no matter what, most oftenly I used it on "AUTO" and 22 degrees, but sometimes summertime I used "LOW" or 18 degrees, and it was very well functioning, until this summer, when I was on a trip to Italy, it rained all day and when reaching the higher altitudes in the mountains, suddenly temperature started to fall and moist started to come on the inside of the windows, defroster didn`t helped, however I tried raising temperature to HI, and to LOW as well, NO RESULT, it just blowed either warm air or cold air, but the MOIST was still there.
When we got to warmer temperatures down from the mountains than suddenly the climatecontrol took away the moist again and it was fully functional in +30 degrees celsius outside, inside it was a nice cool climate again.

This autumn it started to be moist again as soon as colder temperatures arrived, and it gets so BAD that I can`t see out through the windows, I have to open sunroof and sidewindows to let out all that moist, than it gets a littlebit better, but it still doesn`t disappear.

I have talked to a climatecontrol specialist and he said it can be a drainage problem, that the condensed water can not flow out, but I have checked the drainage and the condensewater drip-drops under the car as it should normally, however this happens only inside the garage where the temperature is around +10 degrees, and when climatecontrol is on "AUTO" and 22 degrees, or lower.

The question is why does it smell rotten sometimes inside the car when climatecontrol starts to blow? And why it is only functional when temperatures outside is higher than +5 degrees???
Why do I get all that mois from?

Has anyone any experience about this?

Greatful for any help and advize I can get, thank you in advance!

//Alex:))

If you loose cooling water , the moisty air proberbly come´s from there. Even a very small amount of coling water will give a moisty window due to the glycol in it.
If you don´t loose coling water, it´s a drainage problem , somewhere in the flow of the heated air.
If you get heat in the car it also could come from water inside the car , check if its wet under the carpets

I have not hade this problem with my V8 , so I can´t give you an hint where to look in the airflow or where draining points are, but I have had this problem on several other cars

Bengt

Hello Alex!

I have a 3.6 for the last 3 years and mine did exactly the same thing every time the temperature dropped to 4 degrees or lower.

The answer (as ever!) is simpler than we often think, and it was a faulty servo control on the recirculation flap.
To explain:
The recirculation button on the aircon control panel closes the flap which brings in fresh air from outside, and re-circulates the air from inside the car.
Although i never use it, I guess it can be usefull to provide a quick warm up in cold weather, or to prevent smells / smoke from entering the car when you drive past something.
The key issue to be aware of with recirculated air is that it very rapidly becomes saturated with moisture from our breath, so it's fine if you just use it for a few minutes, but it will always mist up the car if left on long term (because there is nowhere fot the moisture to escape to). This applies to any car with aircon.

The fault on my car was simply that the control flap servo (the vacuum unit which moves it) failed, leaving the flap in a part open / part shut position. Depending on exactly which position the flap is stuck in, the actual mixture of fresh and recirculated air will vary, whic will then define at which temperature the moisture will condense out at!!

The fix is obviously to replace the servo, however as a quick fix, I temporarily screwed the flap shut with a small self-tapping screw through the edge of the flap, into the heater bod housing behind it. This can then be removed at a later date when you've got the servo sorted out.

The flap can be viewed & checked for operation by lying in the passenger footwell and looking at it at the very end of the footwell, at the top (effectively above the passengers toes!)

Bear in mind that if you can hear the vacuum sounds when you press the recirc' button, it doesn't neccessarily mean the flap is operating correctly, it just means the vacuum valving is supplying air to it. The servo may still have a damaged diaphram and not actually push the rod to move the flap.

Access to the servo itself looks a bit fiddly, i think you have to access it from the engine bay plenum chamber area (underneath the bonnet at the base of the windscreen, vertically above the passenger footwell) but requires removal of some of the components there (ducting, fan housing etc..

I've driven mine for months now with the flap screwed shut and it's fine (a bit lazy i know!).

Hope this helps Alex, veilen gluck!

Richard Chaloner
RMChaloner@aol.com

Hi Richard!

Many thanks for your advize! I have found the malfunctioning "FLAP" at the
Aircondition and I followed your advize, fixed it with a screw, and tested
the car in all possible ways, so now everything is working well as before,
and I am very happy about it!

Thanks again!
Best wishes from Sweden
//Alex:))

The recirculation flap can fail in the open position if the small vacuum motor fails, if the vacuum line to that device slips off a connector or if the spring holding the door into the cabin shut either breaks or cuts through its plastic mounting point. If the spring is in place and the door is ajar, then the vacuum device in the evaporator box has stopped working for some reason. I've seen them with a hole worn in the plastic, with the device mounting broken and with the vacuum line slipped off.

While your sheetmetal screw will keep the door closed, thereby stopping the fogging of windows on cold days, the opening is important for air conditioning efficiency during warm weather, so you should figure out what is wrong and fix it.

If you have bad odors from the HVAC system it can be from a plugged drain in the evaporator box. The drain for the box is quite small. It drains out on the passenger side of the transmission just behind the larger drain that evacuates the entire HVAC cavity below the winshield. I've heard of folks unplugging the evaporator box drain tube by using compressed air and by running something like string trimmer string into it.