Air Con Experts - 2.0 TDI A3 - Answer !!

[Crany]

One of my buddy’s who runs a small independent garage has an A3 with non operating air con, the car isn't showing any fault codes, but isn't driving the compressor – any ideas of any common faults on this system ? or how to find the problem ?

 

Turns out after a lot of investigating that there is a shear pin in the clutch mechanism that drives the compressor, such that failure of the clutch won't throw the drive belt off, so it won't show any fault codes !! Not sure yet if you can fit a clutch "housing" or if it needs to be complete compressor - all for a shear pin !!

 

 

Mark.

 

Edited by - crany on 12 Aug 2008 16:56:38

[Don]

 

Wonder if it's my ex-lease car ST04YOG ? - the air-con had conked out on that.

 

I was told the air canister thingy probably needed refilling

 

 

[Stationary M25 Traveller]

My Octavias (probably same system) used an electromagnetic clutch to engage the (permanently-running) drive belt to the compressor. Check fuse and that you have a 12V supply to this.

 

On one of them, the centre bolt that retains the clutch drive plate simply came unscrewed, and the plate fell off - but was left laying on the undershield around the engine. Easy fix - with loctite. Common fault apparently. On the Octavia the compressor is in the offside front corner - just about the lowest point of the engine bay. Easy to check when you undo that corner of the undershield.

 

As long as the aircon is used regularly all year round, the gas shouldn't escape. It is long periods without use that allows the seals to dry out. Re-gassing lubricates the seals and all normally fine again.

 

7 related photos

 

Edited by - Stationary M25 Traveller on 7 Aug 2008 09:52:41

[alicat]

Arrgghhh the VAG aircon/cooling problem ❗

 

I had a 53 plate Golf GTI (TDI 150bhp). It suffered from new with intermittent cooling problems. It would after for no reason do the following:

 

Suddenly start to run warmer than normal in standing traffic, running up to the red zone, then the aircon would stop and cook you slowly.

 

IIRC there were known problems with VAG TDI's around 03/04 as a result of faulty relays & blowing fuses.

 

I would start as already stated by checking fuses, then look at the relays.

 

Alicat

 

 

[blade_runner]

Could be loss of Gas, due to something like a stone damaging the condenser coil, a car aircon specialist would add gas and pop in ultra violet dye to check for leaks.

 

'Pinky Pics' here

[Darryn R]

Hi , If the basics have already been done, ie pressure test system with O F N , recover & recharge system with the correct weight of refrigerant, fuses ok, reconnect diagnostic equipment even if no codes in a/c system .Enter erase codes program, then check for power supply to electromagnetic clutch on front of compressor, if power & earth ok you have cluch fault. If no power, is a/c switch illuminated ? are condenser fan / fans running ? . Has front bumper recently been removed & front panel set into service mode as the refrigerant pressure switch wiring plug has to normally be disconected to do this ? Switch is on o/s.

regards darryn