Also, although it will only be a tiny amount that escapes, I think it will be illegal to vent it to the environment. Just as it is not allowed to top up a system that has a major leak, in order to find said leak.
Air Conditioning fault?
- Thread starter Agile
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It is. The Environment Agency can fine you for deliberate discharge of freons. Of course, it's OK if it leaks out slowly because you got a stone through the condenser, or crashed the car...
Just to be clear, I'm not advocating fully depressing the schrader valves and holding them open for several minutes! Just the tiniest touch for a fraction of a second, will tell you if you've got pressure in there or not! On a healthy R134a system, it could be anything up to 200 psi, depending on the temperature, with the engine not running, but is more likely to be half that. The better way, if you have the requisite gauges, is to just plug the gauges on to the charging ports, but as a cheap and dirty check, if you don't get anything out of the valve under pressure, you know there's no gas in there.
Now if there is no gas in it on a 20 y.o. car should I assume it is just normal leakage and repressurising it should effect a cure?
Or should I expect that it has developed a leak and repressurising will be a waste of money?
Or should I expect that it has developed a leak and repressurising will be a waste of money?
Replacing the valves normally sorts out a lot of leaks.
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I think the answer is "probably not" - or at least, not very well or for very long. Let's assume this is a car with R 134a as the refrigerant, rather than the older R12 (which has been banned since the early 1990s), or the current R1234YF. The problem with 134a is that the lubricating oil is fiercely hygroscopic and forms quite a corrosive fluid when mixed with water. The systems are designed with a cartridge of desiccant in them to remove all traces of water.
Although refrigerant will leak out slowly with time (say 5-10 years), and if that's the only problem, then putting some more gas in it will work fine, the most common cause of total refrigerant loss is a hole in the condenser. This is the second "radiator" that sits in front of the cooling system radiator, and gets pelted with stones and road grit, as well as salty water in winter. Once that happens, the refrigerant escapes, and you create a path for humidity to enter. This then saturates the desiccant. Once that's saturated, you get the corrosive liquid forming.
If I had a 20 year old car and wanted to get the aircon working again, I'd first try depressing the valves to see if there was ANY positive pressure in there AT ALL. If so, it would mean that there's a good chance water won't have entered the system. I'd then (without the engine running) put 12V on to the wire to the compressor clutch to see if I heard a "tick" as the clutch pulled in. I'd then apply a vacuum to the charging ports and see if the system could hold a vacuum for about half an hour. If it could, I'd buy a new receiver / dryer assembly (the bit with the desiccant in it), fit that, and then take it to a Kwik-Fit type place for a regas. However, I'd be taking a gamble that the rest of the components were still in working order. I think some places advertise "cooler aircon or you don't pay"?
However, if there was no pressure at all, I think a 20 year old system would be too much of a gamble. If I was still determined, I might go to a mobile air conditioning specialist, rather than a Kwik-Fit type place, but I'd expect quite a big bill! They have "sniffing" equipment where they can put dry nitrogen into the system and run it, looking for leaks, before they actually put the refrigerant in. The other problem you might run into on an old system, is that most of the joints in an aircon system have o-rings in them, and these will probably have dried out and cracked or at least gone hard, without being in contact with the refrigerant. Likewise the compressor shaft seal. Depending on how accessible all the joints are, you're probably looking at a fair bit of labour to swap all the seals.
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If. Big if. If It was mine I'd take it for a refill where they will pressure test it 1st.
Pay for the test and refill (if it will refill) and hope it lasts.
If it fails the test and/or refill, I wouldn't try any further unless prepared for a BIG bill.
Pay for the test and refill (if it will refill) and hope it lasts.
If it fails the test and/or refill, I wouldn't try any further unless prepared for a BIG bill.
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highly unlikely I think
Only thing I might add, is that I do worry about about these "no-cool-no-pay" aircon regas places, is that they might be tempted to knowingly refill a system that had a leak to get their £60 off you. it'll work for a few weeks, maybe months, and then die again, but they won't care! My dad is in my sister's 2001 Freelander at present. I tried getting the aircon working about 4 years ago when I had it. A local place re-gassed it for me and it worked for the rest of the summer but I could see the wet patch on the condenser. Two years ago I gave it to my dad and a local place re-gassed it for him!
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