Strange leak advice

[Click4]

Hi, just wondered if anybody else has experienced an odd leak like this, I'm stumped presently.

It's a Renault trafic / Vauxhall vivaro / Nissan primastar (all the same)

It was gassed up originally by somebody else, leaked out, and they couldn't find a leak.

I came out had a look, condenser had seen better days and had what looked like oil stained patches on it, removed condenser, checked it 1 night under uv and there was uv traces corresponding to where the patches were... So concluded condenser leak.

Swapped condenser and drier, went back a week later because owner was complaining the airflow wasnt great from vents.

Pressures on suction and discharge all normal, condensation on suction pipe, cold air at vents with chill.

Then 3 days later owner tells me aircon has packed in, I went back and system was completely empty.

Checked system and found no leaks. Except the split rubber seal in valve cap... So concluded that it had leaked due to a possible leak on shrader valve after I'd disturbed it.

Changed valves, new seals in caps.

Pressure tested it, no bubbles anywhere, held pressure, no uv dye.

Vacuumed it, vacuum sounded good, no sounds like it was sucking in air anywhere.

Refilled it.

A week later, I asked owner how aircon was... He replied all working fine.

Then 5 days after that, now complaining aircon not working again. Gone back and completely empty again.

I don't understand how it can go a week, still blow biting cold, still have condensation on suction pipe... Then few days after that suddenly dump it's gas with no evidence of leakage.

I don't know right now if it's a leak eluding me, a pressure relief valve problem on compressor or owner deliberately dumping the gas to get me back because he wants me to fix his airflow problem as well. But either way it's leaked somewhere but not leaving a trace and leaking suddenly after holding up for a week.

[passandscore]

If the system has relief valves I would start there.

[Click4]

If the system has relief valves I would start there.

It may possibly have one on compressor, it's something I was also starting to think of but after having a look at a few photos of compressors for that vehicle I can't see a pressure relief valve.

Will have to get in front of vehicle again on Saturday and take another look at it to identify possible relief valve.

[monkey spanners]

Condenser fans working ok?

[chemi-cool]

Check the flexible gas pipes as well, I have seen leaking .
Compressor shaft seal?

It is something to do with vibrations while running.
Its a same you cant check on the move...

[charlie patt]

Forget that first answer u have to nitro test it for 24 hrs or overnight and sea if it actually leaks then take it from there if it leaks nitro just trace it if it holds pressure overnight then still leaks comp seal faulty ie when shaft spins it leaks, never had a prv leak on a traffic yet and condensor so big fan barely runs if prv does blow customer will hear it even with large radio and u would sea uv dye on back of plug prv up yo 07 back of pump after 07 pump has a blind plug and a fusible plug on high side line by os wing u will find most traffic leaks on condensor .......primary pressure switch or discharge line of comp traffic will still sweat suction line when only half full and if u have poor airflow it may be sweating due to heat load not being transferred to cabin due to lack of airflow ta charlie

[transfreeze]

this sounds like a prv but you should have seen uv dye around it. when using uv dye i have found it only works if the gas/oil is passing the leak.i had a merc in that had a leak the dealer had filled it 6 times with gas and dye still no show.the service port was on the top of the drier on the side of the condenser i only found the leak when i removed the coupler and some oil settled on the base of the stub thought the oil was boiling off along time. cleaned it and sprayed it there it was but no dye.try open all vents in dash set ac to floor vent pressure test with nitrogen + 134a leave for an hour then check foot wells with electronic leak detector. some times i drill a 10mm hole in heater box and test there. be carefull with drill.does the vehicle have ac in the rear also????

[cadwaladr]

Sounds like shaft seal to me,had one that was elusive put dye in it showed very faintly around the clutch

[gravy258]

you say the vac pump sounded allright, don't you use a micron gauge ?
For me its a peace of mind thing.

[IRMechanik]

you say the vac pump sounded allright, don't you use a micron gauge ?
For me its a peace of mind thing.

I'm with you, if you can pull and hold 500 microns you know the system is tight and dry. Even the slightest leak will cause the gauge to rise.

[coolincab]

expansion valve seal nipped ??