A/C weird leak
 

Got an odd issue to pick the collective brains of the forum on - My A/C hasn’t worked for the last 18 months;I went for a recharge and it wouldn’t hold the vacuum so have had a warm cabin ever since.

I have finally got it to my friendly master tech and he’s having difficulty finding the leak!

The system completely fails to hold the vacuum at all, no problem he thought, the leak is that bad that it should be pretty easy to hear when he pressurises the system.

But no, here’s the oddity, it holds positive pressure.

Has anyone else experienced similar symptoms and where did the leak end up being?

If he sticks some dye in there it should be easier to find. Can he pressurise it and see if it is still holding in the morning?

Its the compressor
 

Eventually found the leak by cranking up the pressure to 15bar, turns out the compressor is leaking.

So the next question is whats the difference between the different part numbers? Can I use say a 3.0 petrol compressor in my 3.0TDI? What is the actual difference between a 4e0260895AP and 4e0260895AQ

Cannot find the part numbers you referenced, depending on chassis number it should 4E0260805J or 4E0260805BA for 2004 3.0TDI and E or AG for 3L petrol, don't know what is the difference between them.

I couldn't find them either

They are superseded part numbers.

The sequence for the 3.0 tdi ASB is 4e0260805N-AB-AD-AJ-AP and currently BA

Its made by Denso and is a 6SEU14C compressor type (6 ribbed 100mm pulley).

The AQ model is the same compressor type and pully specs, but is from a 4.0tdi ASE engine. (and has been superseded by the BC variant).

So as they are both the same compressor type, oil capacity, pulley specs - what is the actual difference? There are loads of 6SEU14C compressors from all sorts of vehicles, even refurbs for not much money, so would these fit?

I'm wondering if the situation with compressors is akin to ride height sensors - the numerous part numbers for these are purely for the different connection arms. The sensor itself is the same across load of model & brands...maybe the bolt on bits are all different but can be transferred?

Very interesting. Where did you get those part numbers as even with the latest updates on ETKA, there are no superseded versions of the compressor on any of the A8 models.

I have ETKA 7.4 on my laptop, though the final update is dated 2014.

After an bit of studying, I have come to a working hypothesis:

The compressor itself is standard - ie 6SEU14C, however the ports are modular and bolt on (with the input port forming part of the rear bell housing and housing the control valve) so that they can orientate both ports and valve better for the specific car. Obviously the pulleys are variable to the car and also the control valve (which has different connector options as a minimum). The size of the a/c system determines the oil fill, rather than it being an inherent requirement of the compressor.

Soooo - I think if I were to buy a new/refurb then it should be possible to swap out the relevant modular parts - with the downside being loss of guarantee and possibly never sealing again!

Have you considered getting it refurbished? We have a company local to us that does air con as well as alternators etc


http://www.sacweb.co.uk/airconditioning.html

Makes more sense now you have posted the correct part number :ROFL: