Annoying Windscreen Fog in C5

[begins]

Hi all,

My C5, Year 2007 has this problem of foggy windscreen. I never had such problem with my ex-cars of various brands. I’m wondering whether I’m not used to the way Citroen build its aircon system so I wanted to ask the experts here.

Our weather here is hot and humid, around 31~33c. The foggy situation usually happened during a rain day when weather get a bit cooler or during a late night, around 27c. When the fog is building up on the windscreen, I tried all sort of setting, switching to auto, circulate air internally or letting in outside air, still the fog is there . My usual aircon setting inside the car is between 19c to 21c. The manual mentioned that the recommended setting is 21c.

I also tried to use the front blower button, you could feel air gusting out from front but the fog remain.
The only way is to get rid of the fog is to activate the wiper to wipe away the fog for a moment. This is frustrating.

Kindly advise me and Thank you very much for the help.

Regards,

[Northern_Mike]

Whenever I've had this issue in any car with aircon/climate control it's always been a clogged pollen filter.

Sent from my GT-I9300 using Tapatalk 2

[mooseshaver]

Is the fog on the outside if you use the wiper to remove it? If so that just the air con cooling the glass so much you get condensation on the outside.
I've had it on all my aircon cars if I direct cold air at the windscreen on a hot day. Can't see what you can do about it really.

[evoke]

You might have damp in your cabin from a leaking rubber seal.

[Citroenmad]

I always had the recirculation on my C5 set to auto and it never fogged up. AC should clear your windows if they are.

As has been said, it sounds like you might have a damp or blocked polen filter or damp inside the car.

[Mandrake]

I always had the recirculation on my C5 set to auto and it never fogged up. AC should clear your windows if they are.

Chris, UK weather is very very dry humidity / dew point wise compared to Malaysia, even when its raining. It's a completely different category of climate.

Even in NZ which has a climate half way between the UK and Malaysia, and can occasionally reach extremes of temperature and humidity approaching those in Malaysia fogging of windows is a lot bigger problem than here.

All it takes is a temperature drop after a hot humid day and there will be moisture everywhere. Condensation on the inside of house windows in the evening is common place in NZ in the summer as the air was already saturated when the day was hot, same thing happens inside car windows.

In theory the A/C should help but it would have a lot of work to do to remove that much moisture, sometimes there is no choice but to wipe it off. I used to have bad fogging problems in my Xantia in NZ, giving the inside of the window a really thorough clean (with methylated spirits) helped a lot but it was always a battle in humid weather conditions especially first thing in the morning or in the evening when the colder temperatures promoted condensation.

I don't know about the C5 but the Xantia ventilation system isn't really up to the task for hot humid climates...

[begins]

Hi all,

I tried blocking the air duct just on top of the dashboard and the fog disappeared.

Should I block the air duct permanently? Is there any side effects by doing so?

Kindly advise me.

Thank you very much.

Regards,

[Mandrake]

If blocking the air vent to the dashboard helps it may mean that your heater matrix is leaking putting moisture into the air flow Do you have to top up the coolant regularly ?

[jgra1]

reading through this, little confused

Begins, did you say the wipers clear the screen ok? If that is true then as said it may be the AC making the screen cold and fog forming on the outside..

John

[isisalar]

Begins, I think you've found your own solution. By stopping the cooling effect to the windscreen, the moisture is not condensing on the outside, which is where the mist is, if I've read the description correctly.

[begins]

If blocking the air vent to the dashboard helps it may mean that your heater matrix is leaking putting moisture into the air flow Do you have to top up the coolant regularly ?

Nope, the coolant is working fine. In fact, another option is to turn on the heater and the fog will go away too.

However, in this place, turning on heater is like having sauna on the move.

Regards,

[begins]

reading through this, little confused

Begins, did you say the wipers clear the screen ok? If that is true then as said it may be the AC making the screen cold and fog forming on the outside..

John

You are correct, the fog is forming on the outside.

Regards,

[begins]

Begins, I think you've found your own solution. By stopping the cooling effect to the windscreen, the moisture is not condensing on the outside, which is where the mist is, if I've read the description correctly.

Yes, I'm just a little bit concern about doing so. If the cool air is blocked, I'm not quite sure whether it will find its way to the rear cabin or underneath of the seats and thing like that?

Regards,

[isisalar]

I'm not familiar with the C5 but if you could set the airflow to a face level setting rather than to the screen that should help. The problem is, the screen is becoming significantly colder than the ambient temperature and moisture is condensing on the outside. A little warm air would help, if necessary.

[dnsey]

I'm puzzled:
If the mist is forming on the outside, won't the auto wipers clear it as necessary, just as they would rain?
How does the mist form on the outside on a rainy day, when the screen is wet anyway?
I'm obviously missing something!