Is this causing my aircon issue/leak?

[L-i3wj4]

Mk3 TT and I’ve had air con issues for the past year.
Pretty much works for 2 months and then stops blowing cold.
Been charged 3 times, same 2 months duration roughly each time before stopping blowing cold.
It was pressure tested and held vacuum for a half hour.
Nitrogen tested and no leaks.

All of the above in my opinion pointed to a very small leak somewhere. Aircon specialist recommend dye test next time.

i have done this myself and on the condenser there is a pinhole sized spec of dye (seen with the UV torch). See my photo attached.

Fairly sure this is the leak but given my lack of experience I am looking some confirmation from anyone with aircon experience before I go ahead and order a new condenser.

Thanks all in advance

[finlo]

That dot is on a fin not a tube so possibly not.

[996TT02]

Leaks there (or anywhere) spread, the oil creeps so it's always a patch, never a speck, anyway. You need to check all lines and was a detector used? Also note I know of two instances where the culprit was simply the gas filler schrader valve. If there is a leak an operator who carefully goes over the system with a detector should catch it, they can be set to be extremely (perhaps too, even) sensitive.

[L-i3wj4]

996, you might be into something, I left the car 2 more days, went to unscrew the low pressure cap and it was welded on there. When I manage to unscrew there was the tiniest of pressure release noises (like you just touched your tire valve momentarily). I’m thinking this may be it now. Do they fail regularly the Schrader valves?

[L-i3wj4]

finlo said:

That dot is on a fin not a tube so possibly not.

Think you were correct also, this was maybe some sort of dead insect, I touched it with a screwdriver, it fell to the ground and no dye has reappeared since. It was dark so I couldn’t tell exactly what it was.

[Jaz2000]

The caps on the filling ports are not just dust seals but secondary gas seals and should always be fitted.
That said valves do fail and it may be leaking from there, try it with a gas sniffer which will find very small leaks.

[LennyM1984]

I had a duff Schrader valve on my Cayman's aircon system and like you it manifested itself in a slow leak. I replaced the two valves (only one was actually knackered), got it regassed, and hey presto, working aircon.

Replacing the valves is dead easy if your system is already empty.