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Leak under Car - Air con?

Colonelk

Active Member
Nov 17, 2006
274
0
Hi

I've noticed that after the air con has been on for a considerable time that when the car is statrionary and switched off, water leaks from under the car (looks like its around the back of the engine bay area). If I leave the air con OFF then I don't see that same small patch of water under the car when its stationary and switched off.

Is this normal? Would anyone mind checking their R's with the aircon on to see if it happens on theirs please?

Forgot to add. Its not radiator based as the coolant levels never change.

Ta

CK
 

james_tiger_woo

VW Passat B6 2.0 TDi SE
Jun 19, 2007
353
0
Lincolnshire
All cars with aircon do it - some more than others. Mine's not too bad, but I was parked next to an MX5 the other day and it was like the Nile from the MX5.

Incidentally, I did the whole "paranoid" thing too and checked the liquid come from the car several times (It's just be my luck if it was the radiator!!)
 

si-mate

Jai Ho or Jay Ho?
May 31, 2004
941
0
Kunt Centryside
Air conditioning dehumidifies so you'll find it's worse on a humid day. You should have seen the puddle underneath our new condensers we've had fitted at work.
 

andycupra

status subject to change
as above, the aircon dehumidifies (removes water) from the air.
it has to do this, as cold air is not capable of holding as much moisture as warm air. if you cooled the air and did not dehumidify all the windows would steam up.
 
Jun 1, 2009
423
0
west lothian
Thanks fellas. Nothing to worry about :D

PHEW !! :lol:

Big sigh of relief from me as well,just noticed puddle under car tonight,thought garage had not changed water pump when they changed timing belt.On investigation found there was no glycol in the water so presumed it was either w/washer tank or air con.:think:
 

Muttley

Catch that diesel!
Mar 17, 2006
4,987
31
North Kent
andycupra wrote

as above, the aircon dehumidifies (removes water) from the air.
it has to do this, as cold air is not capable of holding as much moisture as warm air. if you cooled the air and did not dehumidify all the windows would steam up.


To be accurate, the process of cooling the air is responsibile for the dehumidification. Water condenses on the evaporator, the cooling matrix that is in the airflow after the fan but before the heater matrix. And on a humid day, the cold air will be close to 100% humidity, but being cold that means a lot of water has been condensed out, little is left in the air. Once it enters the cabin it starts to warm up and the humidity drops.

That's why you should keep the "air conditioning" i.e. the cooling system, running during colder, wet weather, while setting the temperature higher. The cooling process still squeezes moisture out of the air, which is then heated by the heater matrix (remember it comes after the cooling system), which results in warm, very dry air. Demists the windows in no time.
 
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