Very Slow Aircon Leak

[Ron99]

My 8.5 year-old Insignia's aircon is assumed to have a tiny leak.

After a re-gas it works fine for 6-12 months but then becomes ineffective.

Even with two pressure tests and two lots of UV dye no leak has been found.

It was last recharged early this year but it's now out of gas again.

I've heard about an aircon leak sealant. Would it be worth a try? Any other ideas?

Thanks,
R

[rallycross]

That’s not a leak
Even if it was a very small leak It would be less than 10 days and Then it would stop working.

They can use a special dye that shows up with UV where the leak is - but not when it’s 6/12 months more like 6/12 hours or says maximum.

[Ron99]

rallycross said:

That’s not a leak
Even if it was a very small leak It would be less than 10 days and Then it would stop working.

So when is a leak not a leak?
And if it's not a leak, what is it?



Surely it's not considered 'normal'?

Our other cars - admittedly not quite as old - don't need re-gassing every 6-12 months.

[anonymous-user]

Ron99 said:

Our other cars - admittedly not quite as old - don't need re-gassing every 6-12 months.

Ah yes, but were they built by General Motors?

Joking aside, that's not normal but it's also going to be close to impossible to find. It must be the teeniest, tiniest bit escaping from a seal somewhere to only loose the 400g odd of coolant in a year. Maybe the seals in the AC pump?

It may very well get worse with time and be easier to find.

[jamoor]

Do you use it all year round?

There could be a leak in the evaporator

[A1VDY]

rallycross said:

That’s not a leak
Even if it was a very small leak It would be less than 10 days and Then it would stop working.

They can use a special dye that shows up with UV where the leak is - but not when it’s 6/12 months more like 6/12 hours or says maximum.

Agree, it's not a leak, it's only half a leak.
Similar thing to half a hole..

[Ron99]

jamoor said:

Do you use it all year round?

There could be a leak in the evaporator

Yes, it gets used at various times of the year. In spring-summer for cooling and in autumn-winter for demisting. Car has done about 4-5k since last re-gas early this year.

Now you've mentioned evaporator, it got me thinking that a couple of times in the last few years my wife mentioned a brief faint chemical smell come through the vents when she switched off the aircon.
She said it was the same chemical smell as she noticed immediately after her Zafira B blower recall had been done.

If it's the evaporator on the Insignia that would make sense.

[Petrolism]

There's no such thing as a completely leak-free vessel. Every material, when you look under a powerful microscope, is prone to leakage. No car aircon system will be completely leak-free.

That said, 6-12 months is annoying, since it'll be very hard to detect. If you can be bothered, have every o'ring changed, then if that doesn't work, continue by replacing the pump, which is the most leak-prone component. If it still loses some refrigerant over time, then consider replacing the drier and condenser together, next. Other items are much less likely to fail over time since they're not a moving part (oil seal is the main form of failure on the pump, BTW), or exposed to corrosion. Modern condensers for r134a are very thin-walled. I mentioned the drier, not because they are likely to leak, but because the material inside breaks down over time and can lead to blockages through very small passages in the condenser.

Finally, if a CFC sniffer - Aircon leak detector (Available for around £20) can't detect a leak, there's no way your wife's nose can detect what is a largely odourless gas that is heavy and tends to sink rather than rise, when released.

HTH

[A1VDY]

[quote=Petrolism



Finally, if a CFC sniffer - Aircon leak detector (Available for around £20) can't detect a leak, there's no way your wife's nose can detect what is a largely odourless gas that is heavy and tends to sink rather than rise, when released.

HTH

[/quote]


Probably farted and blamed It on the air con leaking..

[blue_haddock]

This is dead straight forward, it may well have the tiniest of leaks which when they do the vacuum leak check on the ac charging station passes the leak test however as it pulls a vacuum a small leak can be pulled shut.

What you need is an ac specialist who can do a nitrogen pressure test which puts positive pressure into the system and any small leak will be blown open. They will be able to use a sniffer to find the leak and then let you know what needs to be replaced.

[Petrolism]

Nitrogen leak under pressure, compared to 78% Nitrogen by volume already in air?
Hadn't realised it was possible to detect Nitrogen by percentage increase. Simple but clever. Thanks for the tip, good to know.

[blue_haddock]

Petrolism said:

Nitrogen leak under pressure, compared to 78% Nitrogen by volume already in air?
Hadn't realised it was possible to detect Nitrogen by percentage increase. Simple but clever. Thanks for the tip, good to know.

You can't detect nitrogen itself but can use a sniffer to detect any refrigerant alternatively you can use 95% nitrogen 5% hydrogen to pressure the system and then use a hydrogen sniffer to detect the leak. It's more expensive than straight nitrogen but gold standard in ac leak detection.

[stevemcs]

We use nitrogen and its never let us down, more often than not its the condenser, unless its had an accident and the pipes have been disturbed and usually rub on something.