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misting problem
Posted: Mon Nov 24, 2014 2:28 pm
by piglet
Advice very welcome:
Had the car 4 years or whatever but just this autumn I am having severe screen misting issues.
Had the A/C re-gassed and then had them check it again a fortnight later and they assure me the A/C is all hunky dory.
Fitted new cabin filter, fan works, heat works, A/C is reported to work.
Have checked the carpets and can't find any obvious wet. Coolant level is same as always. No smell of screen wash in the car
What am I missing?
Re: misting problem
Posted: Mon Nov 24, 2014 2:42 pm
by benczuk
check the recycle flap isn't stuck shut. (under the plastic at the bottom of the windscreen, passenger side behind the pollen filter if you still have one
The actuators are common failures leading to no fresh air getting in and condensation build up.
Re: misting problem
Posted: Mon Nov 24, 2014 3:23 pm
by piglet
Thanks for the tip,
Removed pollen filter and flap is opening & closing nicely. Not that then.
Re: misting problem
Posted: Mon Nov 24, 2014 3:50 pm
by Welly
It is the a/c itself that's causing the misting, bear with me:
When you use the a/c condensation forms on the evaporator behind the dash which has a drain pan and hose to underneath, above that is the heater matrix. When you park the car you've effectively got a tray of water in there, then when the glass windows/screen cool down the moisture-laiden air in the cabin condenses out and mists up the glass. Sure the a/c will clear it but then begins a vicious cycle.
I recommend NOT using a/c for demisting. The air in Winter is very dry anyway so the heating and ventilation system alone is quite capable of shifting window mist without adding to the problem.
What you need to try is running with no a/c to allow the evaporator and vents to dry out (as long as water isn't leaking in somewhere of course).
Re: misting problem
Posted: Mon Nov 24, 2014 4:34 pm
by rwb
The speed at which the ac clears the windscreen is astonishing, but indeed you can get into a vicious cycle with it.
Sometimes you just have to use it, but I prefer to make sure I've got a long enough journey to keep the blower on high heat for some time afterwards.
Only other thing that springs to mind is whether your condenser drain is blocked.
There's a good howto on the coupe club about it:
http://www.406coupeclub.org/PHPBB3/view ... 45&t=24934