air con not working

rosiedog

A2OC Donor
The air con on my TDi has suddenly stopped working.
Is there anything I should look at before a visit to the garage for a gas check ?
Cheers Graham.
 
Fan does the fan run at reduced speed on the tdi's , maybe look a a.c. compressor see if turning ok

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The air con on my TDi has suddenly stopped working.
Is there anything I should look at before a visit to the garage for a gas check ?
Cheers Graham.


If it is just blowing slightly cool air it MIGHT just be low on gas. Take it to a air-con place (most tyre places do it now) and ask them to check it out and regas it if the compressor seems to be working. They can load it with special dyes to show any leaks.

For around £50 it is worth it for peace of mind I would think.

Steve B
 
Fan does the fan run at reduced speed on the tdi's , maybe look a a.c. compressor see if turning ok

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I am having the same problem, thanks to Steve B for checking for fault codes, none found.I think it is my compresser but not had time to take it to a air con person yet
Richard
 
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The compressor clutch will only engage if the level of gas in the system is correct. Not enough gas and you won't clear the LP trip or the clutch will cycle excessively and too much gas will trip out on HP. Don't try using one of the cheap AC charging kits from halfrauds, without knowing how much gas is in the system you've no way of getting the correct amount in. The easiest place to take it in my opinion is Qwik Fit - Ignore anything they say to you, the only thing you want them to do is gas the system. It's all done by an automated machine and if it doesn't work following the charge, Qwik Fit will not charge you and the machine will vac down the system to check for leaks.

If the compressor does not kick in after the gas has been charged then you can start looking for other issues - when charged the system is normally injected with a flourescent dye so any leaks should be fairly obvious. If there are no leaks then the compressor clutch would be my next port of call which is a fairly simple check.
 
The 'clutch' is not a clutch as such but a single use device to protect the drive belt, should the compressor seize up. It is incorporated into the pulley; to test, check that both the compressor and pulley turn together. If not replace the pulley.

RAB
 
Check the cooling fan in front of the engine runs when AC is on, ALL the time. I had a fan motor burn out, relatively common failure. I also had a slight rise in water temperature with the warm HVAC air☹️
 
The 'clutch' is not a clutch as such but a single use device to protect the drive belt, should the compressor seize up. It is incorporated into the pulley; to test, check that both the compressor and pulley turn together. If not replace the pulley.

Didn't realise the compressor was variable displacement, Audi really didn't spare on the tech!
 
I did say to replace the pulley, but if the 'clutch' has been used, you probably need to change the compressor!

The first thing to do is check for refrigerant pressure with VCDS. Low gas pressure is probably the main reason for failure. The A/C will not function without sufficient pressure and in this case the fan will not run continually when the A/C is switched on. If VCDS tells you that there is no pressure, don't assume that that is correct because the pressure sensor may have failed! So the next step would be to get the pressure checked with a gauge. If this shows zero pressure, get the system filled with refrigerant and green dye; points of leakage will show up under a UV light (an LED light also works well). It is not advisible to take the alternative route of dismantling the system without checking the system with a gauge. The most likely point of leakage is probably the condenser (in front of the radiator), especially if it is original. Replacing the condenser involves removing the front bumper. There are also nine O-rings in the circuit which might be a source of leakage; the two on the compressor are not very accessible and might involve lowering the compressor. It is also a good idea to replace the drier if this is original.

RAB
 
Aircon update.
Had the car in for a check and re gas.
Not a good result, the compressor is leaking, but not from any connections.
Apparently by law they are not allowed to re gas it if the system is not repairable.
Oh well, another task...
 
Changing the pump is a straighforward job with pretty decent access.

If you need a good working replacement pump let me know.
 
Thanks again everyone, now on the 2doo list.
At the Leeds social at the weekend, now preparing to go to Norfolk for three days.
First Job when i get back .
 
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