MISTING Problem

[Denise]

i have a 2000 E320CDi, the problem im having with it is that its misting on the inside windscreen even on short journeys, it was 20 celsius this evening and it was even misting then. Whenever i get into the car and switch the heater on the inner windscreen just complete clouds up for a good 30 seconds before it melts away and then i have to keep the heater on to keep the windscreen clear - This causes the little ones to complain that its too hot! the button in the cigartte ashtray compartment is illuminated and the air recirculation button is off. I have also switched off the EC button (not that its made any difference!), i thought this sort of thing only happened in the winter months and now im begining to worry if something costly is beginning to falter.

Help!

 

[Captain Peacock]

Whatever you got, I also get the same probs at times, in the evening time, suppose its to do with the temp. adjust settings.

 

[BIG Sean]

i have a 2000 E320CDi, the problem im having with it is that its misting on the inside windscreen even on short journeys, it was 20 celsius this evening and it was even misting then. Whenever i get into the car and switch the heater on the inner windscreen just complete clouds up for a good 30 seconds before it melts away and then i have to keep the heater on to keep the windscreen clear - This causes the little ones to complain that its too hot! the button in the cigartte ashtray compartment is illuminated and the air recirculation button is off. I have also switched off the EC button (not that its made any difference!), i thought this sort of thing only happened in the winter months and now im begining to worry if something costly is beginning to falter.

Help!

Switching off EC button??? this means you are turning the aircon OFF- if it is lit up red!!!! EC stands for ECONOMY

 

[nigel cross]

Have you checked your water level in your rad, my brother had a similar problem, it turned out to be a minute hole in his heater matrix

 

[Rory]

Whenever i get into the car and switch the heater on the inner windscreen just complete clouds up for a good 30 seconds before it melts away

This sounds normal to me. If you use the car during the day with the a/c on, then then the system is left wet. When you restart the car that wetness is blown through and mists up the windows. It should quickly clear as the a/c gets going. All cars do this to some extent.

If you turn the a/c off (by pressing the EC button) it might never clear - my C Class is like this, and so is my wife's Jazz.

What I try to do, is switch the a/c off a couple of miles from home, in order to dry out the system. But I drove my daughter's Ibiza 10 miles last night with the a/c off, then left it an hour, then started it again and it steamed up straight away. I think it's just been very humid for the last couple of days.

 

[BTB 500]

This sounds normal to me. If you use the car during the day with the a/c on, then then the system is left wet. When you restart the car that wetness is blown through and mists up the windows. It should quickly clear as the a/c gets going. All cars do this to some extent.

If you turn the a/c off (by pressing the EC button) it might never clear - my C Class is like this, and so is my wife's Jazz.

What I try to do, is switch the a/c off a couple of miles from home, in order to dry out the system. But I drove my daughter's Ibiza 10 miles last night with the a/c off, then left it an hour, then started it again and it steamed up straight away. I think it's just been very humid for the last couple of days.

Yup, agreed. Our Jazz often did this too, although the climate control in my VW is more sophisticated and (in auto mode) doesn't run the fan until the aircon is de-humidifying.

 

[PJH]

Have you checked your water level in your rad, my brother had a similar problem, it turned out to be a minute hole in his heater matrix

My thoughts too. If it is a leaky heater matrix you will probably smell the anti-freeze.

 

[MangoMan]

Yeah, Rory is right there.

If you use the A/C a lot, you will get this happening. The A/C radiator behind the dash actually gets covered in ice, thats why you see water dripping from the bottom of the car after you have stopped, it's the ice melting and running out the drain.

If you have been using the car with A/C and then park it up some of the moisture vapourizes into the cabin, creating artificial humidity in the cabin, and also all the water hasn't drained away in the radiator. So as soon as you start the car with the fan on with the direction up to the windscreen it condenses on the relatively cool glass, causing 'mist-up'.

The solution I found was to, as stated, turn off the A/C before end of journey and direct air to the footwell, so when you start up again air will not be directed to the windscreen. And oh, open the window.

I hope this helps.

Cheers, Bill.

 

[BonzoDog]

Excuse my dumb question

Yeah, Rory is right there.

If you use the A/C a lot, you will get this happening. The A/C radiator behind the dash actually gets covered in ice, thats why you see water dripping from the bottom of the car after you have stopped, it's the ice melting and running out the drain.

If you have been using the car with A/C and then park it up some of the moisture vapourizes into the cabin, creating artificial humidity in the cabin, and also all the water hasn't drained away in the radiator. So as soon as you start the car with the fan on with the direction up to the windscreen it condenses on the relatively cool glass, causing 'mist-up'.

The solution I found was to, as stated, turn off the A/C before end of journey and direct air to the footwell, so when you start up again air will not be directed to the windscreen. And oh, open the window.

I hope this helps.

Cheers, Bill.

Is it the case that the water that freezes is condensation i.e. water extracted form the air or, is it water from the system?
If it is the latter from what part of the system and at where should I look to replace it?

 

[MangoMan]

Airconditioning extracts moisture from the air, this freezes onto the condensor/radiator behind the dash. When you switch of the A/C or the Engine this ice melts, most of it is drained to the outside, under the vehicle. What is left causes the atmosphere inside the car to become moist/humid. So when you start the car with air directed to the windscreen, the moisture in that air condenses back to liquid on the cooler windscreen, causing it to mist-up.

Personally I don't think there is anything wrong with your system, it's just that it's been quite humid lately, averageing 65%, creating more build-up of ice/condensation.

So it is the water extracted from the air by the airconditioning.

Try not using your A/C for a couple of days to see what happens.

Also, the only other thing I can think of is that the drain for this could be blocked. If this is the case I'm afraid I can't help you there, you would have to take it to a Garage to get checked out, sorry.

Hope this answers your (not dumb) question.

Cheers, Bill.

 

[Rory]

Is it the case that the water that freezes is condensation i.e. water extracted form the air or, is it water from the system?
If it is the latter from what part of the system and at where should I look to replace it?

It's water extracted from the air.

On some cars the evaporator (as the 'radiator' is called) drain can get blocked so the water doesn't drain away and that obviously makes matters worse.

It's just one of those things that some seem prone to - I've had cars where it was almost impossible to turn the a/c off while on the move without the car steaming up. In fact my C Class is like that, although on auto, with the inside and outside temps balanced there's very little airflow, which doesn't help.