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Fog from air vents and water in footwells


ClioSport Club Member
Two issues here:
1. After running the air con for a long while - and when it's working hard - I sometimes get fog coming out of the centre vents
2. The cabin has a musty smell and sometimes the driver's side mat is wet

I know about some drain holes in the scuttle, but are there others for the air con system?

If anyone can offer some hints and tips about these two issues I'd be really grateful!


ClioSport Club Member
  850 T5
Different car, granted, but I had these symptoms when the condenser/heat exchanger in my volvo started to leak behind the dash. Musty smell and mist out of the vents and passenger footwell was damp…


ClioSport Club Member
This might help, my 182 has air con deleted, but the condenser is still in place. The photo shows that it's in the air duct in the 'scuttle' just downstream of the fan.
It will of course produce loads of condensation in this weather.
What I can't get a photo of is the rubber drain pipe that drops from directly under the condenser to the bottom of the bulkhead, attached to the bulkhead by a small locating pin.
My guess is that is blocked, but good luck getting to it! I cleared mine out when the engine was out.


ClioSport Club Member
Correction! That is not the condenser, too many cold cans on a hot evening!
I'm not sure what this is officially called, I'd call it a cooling coil, but cooler matrix?
(The condenser which was at the front and cools the hot fridge gas has gone from my car)
  172 Ph1
Erm , looks like your air con is non functional ?
Is that correct .
Anyway moving on .
Mist coming from air vents with air con not functioning will 100% be coolant spray from a leaking heater matrix . The spray from a poss pin hole size leak is getting into the heater air flow and being blown out through vents .
Also the smell you go on about will be evident also.

If air con is functioning correctly , then same rules apply , but this time it’s a leaking evaporator giving the same symptoms and a smell.

So if the coolant level is going down ever so slowly and you can confirm the wetness on the floor is the same fluid that’s in you coolant bottle , then you’ve found the culprit.

Sent from my iPhone using Tapatalk


ClioSport Club Member
Erm , looks like your air con is non functional ?
Is that correct .

That is completely correct, the photo was just to show the rough location of the evaporator.

I may have this wrong, if so please tell me, but in humid weather with AC working the condensation produced by the evaporator needs to drain away, which is why there is often water under a car that has been stationary after the AC has been running??
If the hose that drains the condensation away is blocked the condensation will collect in the duct??
I thought it might just be worth checking the drain hose that runs down from just under the evaporator position.

From what you are saying though, that can't be the problem so the OP shouldn't bother checking that.

My experience of AC only comes from Building HVAC systems, so an education in auto AC would be welcome