DIY aircon leak detection?

I suspect not. It's not as if there is very much fluid in there, so a tiny leak will soon cause it to fail. My belief is that garages locate leaks by repressurising with a fluorescent dye added and then use a UV light.

Kwik Fit will identify a leak at their expense.

Kwik Fit have also been known to take a car with a/c that works but not as well as it should, suck out all it holds, and report that the a/c's bust and it needs major work; while an a/c specialist 2 days later finds all that it needs is regassing.

Well yes but the fluid content is irrelevant if I?m pressurising it with air.

It?s been to a Halfords and my regular garage, neither has identified the leak so this is why I?d quite like to try myself.

Tim

I thought that the machines they connect to automate the regass process would detect some faults as all the gas is first removed, a vacuum is then applied to dry out the system and new gas/oil, and optional leak detection dye, is added. The print-outs I have been presented with when re-gassing A/C have shown the amount removed, the vacuum level and duration and the amount of gas replaced.

Leaks in seals may not be detected during re-gassing as they re-seal with a vacuum in the system. The fluorescent dye should show up leaks afterwards.

Don't use air it's too damp and will contaminate the system. Use CO2 (keg?), will make bubbles just like air. You can also get CO2 detectors but it would have to be in a draught free location. CO2 is inert and won't damage any seals or the drier.

You should also use a fill hose with pressure gauge that's a screw fit on the low pressure valve.

CO2 is being used in some newer air-con systems as refrigerant.

If the leak can't be found by UV detection it's somewhere concealed, like the back of the condenser between it and the radiator or in the evaporator matrix in the heating duct.

Rubbish.

They don't fix air con systems and don't charge if the re-gas doesn't work.

None of which conflicts with what I reported from my personal experience accompanying a friend. (I did tell her she'd do better letting me take her car to the specialists I use but she wanted to try a quick trip to the local KF.)

AIUI that is all true /if/ the machine is connected and used properly.

No prints-out were provided. She was simply told that her car's a/c needed major work. When I pointed out the compressor had been working when she drove in I was told I must have been mistaken.

The a/c specialists told me it's a familiar story.

This can be a problem with franchises - while they're branded and probably tooled/trained/financed similarly, they can still vary, depending on the staff.

Pretty sure the UK operation is all directly managed rather than franchised.

nooooooooo, if you want to pressurise it, you MUST use an inert gas such as nitrogen, add some flourescent dye and use a UV light to detect a leak. Air/water inside will kill your air con system.

Get a professional to do it is the best advice.

Sorry I misread the OP

I assume there is a mechanical seal where the drive shaft goes into the compressor. This may be very difficult to see without removing the unit. Halfords don't have a great reputation for competence; have you confirmed whether your own garage has all the proper kit including the vacuum extractor for recycling, or do they just use a DIY can around the back when no-one is watching, I wonder?

Good points

Which might make it even more likely to be staffed by minimum wage monkeys.

Cheers, it was just an idea.

Tim

I?ve only had to had one a/c system topped up- I consider the remarkably good luck, it certainly wasn?t due to anymore than running it regularly. I wasn?t sure if there was a real leak or it was just the normal slow loss I understand some are prone to. Fortunately, Group On had an offer with ATS from memory- a a/c top up for about £20 or so- around half price and cheaper than a decent DIY kit to do it.

There checked it, topped it up, it is still working 3 years on. (I don?t own the car now but it stayed in the family.)

Group On have repeated the offer, number 2 daughter got a voucher later for her car.

So, if you can, perhaps wait for a bit to see if the offer comes around. I?ve not needed it so haven?t been watching for it but other offers do repeat.