Car Ventilation

[bobski1]

Had this problem for a few months but got to the point of really needing to look at it & get it sorted.

Some time ago the car started to suffer from condensation on the inside, thinking it could have been from a rainy day & wet feet I put some cat litter in a sock to try it out. It didn't really have much of an effect. I have even left a dehumidifier in the car over a weekend and there wasn't anything in it which leads me to think the damp is coming from somewhere inside the cooling system.

Putting the air con on was really efficient at the start but that is also now starting to lose it's effect. With normal air ventilation on (non air con) the car steams up within minutes on all windows.

Having the windows open helps but its bloody cold.When I do put the windows down and up there are actual water droplets on the inside which look to be coming from the internal strip on the door.

I have checked the carpets and boot and none of it feels damp

Something tells me it could be to do with the ventilation system but I can't say I've had it this bad when now even the air con is struggling to shift the damp.

[Willy Nilly]

Check the drains on your air conditioning, legionella lives in that, so it needs to drain away for that too.

Then check very carefully that water isn't getting into the car somewhere. Are all of the windows fully up? Check where the water drains off the roof and windscreen. Check it's not got a hole in the heater matrix, you'll likely smell the antifreeze and will notice the engine is loosing coolant.

[vikingaero]

(1) Check the air input is on Fresh air from the outside and not recirculate
(2) Lift all mats and check for wet carpets.
(3) See if the flaps in the boot/behind the bumper are swinging to allow air through.
(4) Accept that sometimes the cold air/humidity/damp interior, wet shoes/clothing/breathing will overwhelm any attempts to defog.

[GreenV8S]

Antifreeze has a very distinctive smell in enclosed spaces so you would know if it was a cooling system leak. I suspect you'll find that there is a leak somewhere letting rain in faster than you are able to dry it out.

You may be able to dry it out faster by using a towel to dry off the windows at the start of each journey rather than relying on the demister. The demister makes the air damp and the water will condense out again at the end of your journey (usually on the windows since they cool down fastest). Don't leave the damp towel in the car - take it with you and get it dried out before the next journey. It will only take a small leak to beat you though so really the only solution is to find the leak. One way is to have a helper gently dribble a hose around all the windows and door shutlines while you watch for any signs of water on the inside.

[Sheepshanks]

What car is it? Some seem to need the a/c on pretty well all the time.

[bobski1]

I might add that when switching air con off to normal air & sometimes with the aircon there is a musty/stale smell - could this be the coolant leak?

Possible heater matrix leaking?

It still does go hot & cold but I'll check the coolant level tomorrow as well as having a feel of the carpets again.

It's on the daily seat Ibiza 1.9tdi, after googling it more this evening it could be

Heater matrix pipes
Blocked drain holes
Leaking matrix

I don't really know where the heater matrix lives or where the drain holes are to being checking them.

Could be a dash out jobbie

Edited by bobski1 on Wednesday 23 January 00:03

[GreenV8S]

I'd have thought it was more likely a sign that the whole heater/ventilation system was damp. That might be a clue that the fresh air intake in front of the windscreen has got a blocked drain.

[E-bmw]

bobski1 said:

I might add that when switching air con off to normal air & sometimes with the aircon there is a musty/stale smell - could this be the coolant leak?

Possible heater matrix leaking?

Your first point is true of ANY A/C car , so ignore that.

If the water was coming from The heater matrix or associated pipework you would be constantly topping up your coolant water in the engine bay.

Look under your wipers/in that area, there is likely to be (in each corner) a drain to allow water to drain out of the scuttle, these are probably clogged with old leaves etc & this will be allowing water to run through into the footwell area, clean these out if that is the case.