Air conditioning won't stay on

[wanstronian]

Hi all,

I got in my '99 2.5 TDi this morning and discovered that the air con doesn't seem to work any more (it was fine last night). When I press the button the little snowflake symbol lights up, but goes out again as soon as I release the button.

Anybody know what the problem might be?

Thanks

W

[gazza57]

I suspect Wanstronian,
That you have lost air con compressor pressure, the gas may have leaked out together with some compressor oil it's dissolved into.
The system usually has an interlock to prevent the compressor running with low or no pressure to protect the compressor pump seals.
Check your system pressure and have an ac service every two years, costs about 75-100 quid, they remove the old oil and gas which like brake fluid absorbs moisture from the atmosphere and fill the system with hot nitrogen which is circulated for an hour to remove all traces of moisture, if there is a dessicant or coalescer filter, ie moisture trap, change that too.
Fail to do this and moisture will build up inside the system and eventually it rots from the inside, new compressor= serious wallet assault!
They then refill with fresh refrigerant and charge to the correct system pressure.
Usually a flourescent dye is added to help to spot leaks more easily.
Have you run the ac every week, or has it been off a while?, sometimes you get a leak if it's been off a while.
Run it once a week for an hour right through the winter, this will help to keep the pump seals lubricated and stop them passing gas.
I run mine all the time, you lose a little economy but the ac is always pucker.
Hope this helps
Gazza57

[bora(ing) nick]

Hi all,

I got in my '99 2.5 TDi this morning and discovered that the air con doesn't seem to work any more (it was fine last night). When I press the button the little snowflake symbol lights up, but goes out again as soon as I release the button.

Anybody know what the problem might be?

Thanks

W

Why do you want the air con on..... It's bloody freezing outside

Don't worry about it til next summer.....

Nick

[wanstronian]

I haven't been using it as much since the weather got a bit cooler, but I had it on last night on the way home from work.

I'll try and find a local aircon specialist and get them to diagnose (don't want to pay main dealer prices!). I'll let you know if your guess was correct!

Nick - haven't you heard - there's going to be an Indian Summer... any day now... just wait... you'll see.........

Thanks

W

[gazza57]

Why do you want the air con on..... It's bloody freezing outside

Don't worry about it til next summer.....

Nick

Just run it with say 20 deg c selected, it will still be warm and will exercise the compressor as I stated earlier.
A lot of people just turn it off in winter and forget about it, but if you do it will cost you.

Gazza57

[gazza57]

I haven't been using it as much since the weather got a bit cooler, but I had it on last night on the way home from work.

I'll try and find a local aircon specialist and get them to diagnose (don't want to pay main dealer prices!). I'll let you know if your guess was correct!

Nick - haven't you heard - there's going to be an Indian Summer... any day now... just wait... you'll see.........

Thanks

W

The price I quoted was an independent which I use locally, I suspect a main dealer would want something in the region of a small country's balance of payments deficit to do it and anyway they usually sub it out to an independent but charge you normal dealership labour rates.
Gazza57

[mluton]

I could be wrong, but as the weather is getting cold it doesnt engage the aircon if the temp is below 5 degrees.

Safety precaution so it doesnt start up with a frost on the system, which will kill it.

[adamss24]

You're right, the compressor wont work below 5 Celsius. It will briefly work if you press the demister button for the windscreen.

[stonedagain]

Yopu can use aircon at any temperature you want to. At higher temperature settings, the aircon dries the air inside your car (Great for quickly demisting the car in cold or damp weather!)

[Dancake]

My Leon would turn the air con off if it was cold outside and the snowflake symbol was on. (less than 5 deg as earlier post states) Probably the same on Audi?