interior demist with climate control

[kev64]

with the heavy rain we have had these last few days and the worst since picking up my car last month a potential problem may have come to light??? I am finding the only way to clear the interior misting when it is raining is via the demist button on my climate control. However should this be the case as this is just consuming more fuel and try as i might i cannot find another heating setting to stop the car misting up from within. Any advice would be most welcome

 

[nightflight]

turn the heating on as high as it will go, blow it over the windscreen, then when the car's proper toasty, open the window a fraction and watch the car suddenly become mist free. then keep the heating on somewhat to keep the glass warm and mist free

that said, isn't the "demist" setting on the clima control for that purpose?

 

[Nath.]

If you've got the recirculation button off and you are getting this problem you must have some seriously wet clothes on.

 

[John33]

We have major problems with condensation and it takes ages to clear in the morning or after it has been left all day. The car has the basic air con and everything seems to work as it should. Its so bad Ive been looking for wet carpets or pools of water in the boot but all looks dry.

Any ideas ?

 

[EdHorny]

Doesn't the car get heat from the engine? I found with my Boc and the climate control, hit the heater button, take AC off, close vents so all heat hits windscreen, if you want you can direct the 2 side vents onto the driver and passenger windows. When the window clears or it gets warm, open the window a quarter, let the air cool, then close, repeat the process, I had a slightly wet coat on and so did my passenger and this cleared the car a treat. You can turn the climate control off after, but as soon as you see the windows start to mist, wack it back on to prevent it.

ED

 

[John33]

To give you an idea of how bad it is. Tonight the car was driven home 15 miles and arrived just after 5pm. At 6.45 we got in the car to go shopping - all the glass was very wet inside and at first we had air con on and after a few min warm air - all the time on setting 4 ( full ) and directed at the screen. There was no sign of the screen drying out for the first 5min !

 

[predo]

i was just about to ask the same thing! it gets really misty, for example after coming back from work in the evening, within one hour car is all misted up. In the morning its just the windscreen really and it takes good 4/5 minutes of blowing warm air with aircon on to demist it. On my previous car it was almost instantaneous. Could it be that aircon isn't drying air good enough?

 

[Nath.]

Have you got leaves blocking the heater intake in the scuttle?

Maybe you have had in the past and now your pollon filter is wet?

 

[predo]

how to get to it in mk2?

 

[EdHorny]

I had that with my last car, but that was because the passenger door was leaking, so a good rain would soak the passenger footwell and then in winter I'd get in and the inside of the windscreen was frozen. I kept a shammy leather in the car and cleared the windows as soon as I got in, this removed the moisture straight away. I think the issue is that there's moisture in the car, when you put the heaters on, they aren't hot at first, then when the engine warms up, the air gets hot. Then the moisture evaporates into the air, but then you get too warm, turn off or reduce the heater too much and the warm air condenses onto the screen again, thats why when the wiindows do clear, when the heat is there and you need to open the windows to dump the moist air out. But moisture will then be created again from your breathe. It happens in most cars. I don't think it's an issue with the car and I don't think that car demisters work great anyway.

Don't forget, heat comes from the engine, give the heaters a chance and dump the moist air. Best advice I can give.

ED

 

[nightflight]

Once my windscreen's demisted i tend to leave the aircon on about half way temp and speed 1 or two blowing constantly over the windscreen, keeps the car at a nice temperature and keeps the windscreen inside at the same temperature as the car so it doesn't mist up.

If you think there's excessive moisture in the car, try having it blowing hot air on full speed into the car with the air con on, til it's really hot in the car, then open the windows til it cools down, repeat that several times over? Your car mats aren't a bit damp are they? they could be soaking up the water from your shoes and being the source of moisture

 

[Nath.]

BTW "CC consuming more fuel" This is true but only about 1-2MPG, the same as driving with the windows open as this upsets the aero of the car.

 

[Hank]

Just a thought but have you guys got the air recirculation on at all as when this is on it will mist up quickly as it just circulates the same air in the car round and round and if it is on the windows it will have the air your breathing out which is very moist blasting on the windows.

 

[John33]

Just a thought but have you guys got the air recirculation on at all as when this is on it will mist up quickly as it just circulates the same air in the car round and round and if it is on the windows it will have the air your breathing out which is very moist blasting on the windows.

With the basic air con the air recirculation goes off if you turn the dial to screen demist.


The car is dry on all the mats and under the mats. Leaves have been removed from the air intake.

The car that this one replaced was a 17 year old Polo and that had a good demist system. This one was new on 21st Sep 09

 

[John33]

So this morning 8am start - everything was nice and dry and with no air con used it stayed that way.

Yesterday the air con was on at start up and a load of condensation came in I think.

 

[techie]

BTW "CC consuming more fuel" This is true but only about 1-2MPG, the same as driving with the windows open as this upsets the aero of the car.

Also our modern compressor are constantly driven, no magnetic clutch these days so even when the a/c if off the compressor is being driven, the load does alter however but its always running to keep the system moving and lubricated.

Also having the a/c on will demist quicker, it de humidifies the air. You can have a/c even with heat.