Aircon Problem But Not A Leak!

[Ogben Schmutzel]

Hi All,

 

Anyone got any ideas on this? Its on my Alhambra 1.9 TDi (115 bhp) SE with climate control.

 

Few months ago I noticed that although around town the aircon works fine, at some point on a long run (ceratinly 90 miles seems enough) it stops working.

 

So as a starting point decided to have the aircon serviced as it was due - about 3 years. Anyway no problems reported. Garage looked at the diagnostics too and no faults found. No loss of pressure or anything and I do trust the garage that does this for me.

 

After the service I tested again and around town, on lowest setting and with the fan speed at about 30% the vent temp drops to about 2C with the ambient at 26C (this was the hot weather a couple of weeks ago). So I was dead chuffed. That'll sort it I thought!

 

Did the long run again today and as before on getting there with the same test as above the vent temp only drops to about 10C with the ambient at about 21C!

 

Get home, engine cools test again and all is fine again!!!

 

Any ideas?

 

Cheers.

Oggy.

[Bigjeeze]

If you have climate control then it's probably just doing it's job - with an outside temp of 26c it will cool much more powerfully until the correct temp is reached then it will wind down. Try it on the lowest temp and see what happens ( ie no indicated temp just low)

[Ogben Schmutzel]

Hi Bigjeeze,

 

Thanks for replying. That's exactly what I did, I thought my post made that clear but maybe not. Its def not the CC just doing what it does!!

 

Regards.

Oggy.

[sepulchrave]

Cooling fan failure?

[Ogben Schmutzel]

Hi Sep,

 

Sorry, not sure what you mean. Do you mean the fan that controls flow into the cab or something else? If the former then that still works fine.

 

Thanks for responding.

Oggy.

[big_kev]

The aircon system has a condenser ( big radiator at front of vehicle ) which gets hot and requires cooling. The condenser is in front of the ordinary water radiator and they are both cooled by a large fan ( possibly 2 fans ).

 

It is likely your aircon is ok when the vehicle is cold but as the condenser and radiator get hot the fan is unable to cope ( will be worse in hot weather ).

 

The flow of air through the radiator when driving at speed should be sufficient to cool them down but the fan may still be needed.

At low speeds the fan is definitely needed.

[Ogben Schmutzel]

Hi Kev, thanks for that. Have to admit that does describe it pretty well. At motorway speeds there was limited cooling but in town it was virtually nil, coming through at ambient!

 

Next day, even around town, it was fine again.

 

Thanks again.

Oggy.

[gregers]

something my better half found today,is if you put the setting on recirc its colder?ONLY TAKEN US 2.5 YEARS TO FIGURE THAT OUT :( :P

[Bigjeeze]

Are the fans coming on immediatley? When the aircon is on they should be on all the time - Maybe they aren't working properly

[Ogben Schmutzel]

I work pretty local so don't the chance to test exactly how far I have to go before the cooling starts to fail, but certainly 90 miles is far enough. But I did about 10 miles comming home today and checked the fans and both were belting away. Also, don't know what part of the circuit it was but one of the aluminium pipes was really cold and running with condensation and a similar pipe the other side was red hot. But the aircon was working ok and like I have said above was getting down to 2C at the vent when over riding the climate by putting it on low - I had checked it on the way home. Paranoia is on overtime at the moment.

Thanks for all the suggestions!

Oggy.

[Bigjeeze]

One pipe should be hot the other cold if it is working correctly - Maybe as suggested there is an temp sensor that is working intermittently. Have you tried VAG Com?

[Ogben Schmutzel]

Update: Just got back from a 100 mile run and as before aircon was not cooling properly. Forgot to check the fans etc, but on going out to the car a couple of hours later I notices that the ammount of water that had run off from the aircon drain was much more than I had ever noticed before.

 

Is it posible that it is freezing up?

 

Cheers.

Oggy.

[Bigjeeze]

One pipe should be hot the other cold if it is working correctly - Maybe as suggested there is an temp sensor that is working intermittently. Have you tried VAG Com?

 

Sounds like you have a sensor not working - Get it checked on VAG Com.