Where does the AC system usually leak?

[Aj77]

I've read it's at the join between pipe and compressor does anyone have any experience?

 

If it is at this join is it an easy job to put a new seal in?

[GreenMachine1.6]

My 2007 had a leak in a lower bottom corner of the A/C radiator (condenser) in the engine bay due to corrosion. A very very slow leak that grew over 2 to 3 years.

[munster]

Could be as simple as a hole in the air con radiator!

[Breezy_Pete]

I bought a cheap UV LED torch off ebay which shows up leaks if there's ever been any dye put in the system.

Not sure if it works if there hasn't ever been a recharge with dye.

Greenish glow  shows leakage if I remember rightly.  Will need to be dark outside, or close to it, for best visibility.

 

 

[J.R.]

Aj77, do you know what your system pressure is?

 

An Octavia 2 will have already needed a recharge by now through normal refrigerant losses through the flexible hoses, O rings etc without any of them needing replacements.

 

The G65 refrigerant pressure sensor often fails through corrosion where water sits on the aluminium casing which will cause the system to lose its pressure.

[Aj77]

12 hours ago, J.R. said:

Aj77, do you know what your system pressure is?

 

An Octavia 2 will have already needed a recharge by now through normal refrigerant losses through the flexible hoses, O rings etc without any of them needing replacements.

 

The G65 refrigerant pressure sensor often fails through corrosion where water sits on the aluminium casing which will cause the system to lose its pressure.

 

I have the pressure gauges / hoses kit, I will measure the pressure later today but I'm sure the needles won't move as the compressor needs to be running and I don't think it runs when the system has no R134a in it.

 

 

[Breezy_Pete]

Here a couple of images from the UV torch (of our 2005 mk1 Fabia). 

High pressure connections to expansion valve and condenser IIRC.  I subsequently found that the output connection at the compressor was worse than both of these, and apart from access to the latter, none were too tricky to get at to swap in new o-rings.

 

 

Edited 19 March, 2021 by Wino

[Aj77]

1 hour ago, Wino said:

Here a couple of images from the UV torch (of our 2005 mk1 Fabia). 

High pressure connections to expansion valve and condenser IIRC.  I subsequently found that the output connection at the compressor was worse than both of these, and apart from access to the latter, none were too tricky to get at to swap in new o-rings.

 

 

 

Interesting, I've ordered a bottle of r134a and will get some dye also, the only thing a home mechanic can't do is legally evacuate the Freon but I shouldn't need to do that as it's empty anyway.

 

I might see if I can get an o ring set, I'd still need a vacuum pump to vacuum the system.

[J.R.]

You never said that your system was empty, that was why I asked what the pressure was.

 

Like you I invested in the test and filling equipment, you will need the vacuum pump for refilling from your cylinder.

 

My leaks in the past have always been from where I have refitted a compressor and damaged the O ring on the large connector when refitting it, in hindsight each time it happened I felt some resistance.

 

The VAG O ring sizes dont come in the boxes of assorted O rings, they are larger & a different cross section.

[J.R.]

If you cannot pull a vacuum to test then it means that the leak has already allowed the system to be filled with damp ambient air, aside from whether you replace the drier cartridge when you do get it up and running it means you have nothing to lose by compressing the system with air to test for leaks with soapy water.

[Breezy_Pete]

I wonder if much/any ambient air would really enter? Once there's no pressure difference, there won't be anything to promote much flow in or out. Thermal cycling of engine bay will do a bit I guess.

Very dependent on size/cause of leak I guess.

[J.R.]

You are correct Wino, however if you have vacuum tested it only to find that it has a leak then in doing so the system will have been purged with ambient air. Hence my comment starting with "if you have vacuum tested it....................."

 

I have recharged several systems that have been open to the elements without changing the drier and there have been no ill effects, the procedure says to leave the vacuum pump on for 45 minutes/one hour etc yet it pulls the full vaccum within a couple of minutes, I wondered whether this would be to allow time for any moisture to vaporise and be evacuated?

[Aj77]

5 hours ago, J.R. said:

You never said that your system was empty, that was why I asked what the pressure was.

 

Like you I invested in the test and filling equipment, you will need the vacuum pump for refilling from your cylinder.

 

My leaks in the past have always been from where I have refitted a compressor and damaged the O ring on the large connector when refitting it, in hindsight each time it happened I felt some resistance.

 

The VAG O ring sizes dont come in the boxes of assorted O rings, they are larger & a different cross section.

 

I'll just be refilling from the r134a can don't need a vacuum pump for that.

 

I'm just going to add a few drops of dye and refill the system. That's what kwikfit (if your in the UK) said they would do, and I'll monitor it, maybe I'll get cold air and the air will leak out over the next days/weeks.

 

Maybe I won't get cold air and the compressor is shot.

 

So either way it will tell me what's going on.

 

If it doesn't hold gas it will need the full evac/repair leak/compressor/vacuum/refill.

 

As for the oil that's trickier unless you fully remove the compressor.

 

I do really want to get it working though as I don't do well in a hot car, I sweat like crazy and it's very uncomfortable.

[J.R.]

If your system still has some charge then you will be able to top up with the cylinder, are you buying a proper 6kg one or the Chinese camping gaz type cans? I started with the former and then supply problems (the tin cans are illegal in europe) forced me to the proper cylinder which no compliant seller will sell to an individual without the required certification, some of the eastern european E-bay sellsrs will though.

 

If you have a leak or replace any component like an O ring then if you try to refill from your cylinder without a vacuumpump you will only get a partial charge in there and it will have 20-25% of air floating about, dont even think about trying it, vacuum pumps are not too expensive in the scheme of things after spending £30 on guages, £200 + on an R134a cylinder etc.

 

Where it gets really expensive is the equipment to recover & recycle the existing regrigerant gases without creating your own personal hole in the ozone layer.

[J.R.]

You wont be able to add oil or dye unless they are in containers pressurised to 4 or 5 bar, with a vacuum pump and guage kit its very easy to draw in any fluids, maybe some of the Chinese refill cans contain dye?

[Aj77]

24 minutes ago, J.R. said:

If your system still has some charge then you will be able to top up with the cylinder, are you buying a proper 6kg one or the Chinese camping gaz type cans? I started with the former and then supply problems (the tin cans are illegal in europe) forced me to the proper cylinder which no compliant seller will sell to an individual without the required certification, some of the eastern european E-bay sellsrs will though.

 

If you have a leak or replace any component like an O ring then if you try to refill from your cylinder without a vacuumpump you will only get a partial charge in there and it will have 20-25% of air floating about, dont even think about trying it, vacuum pumps are not too expensive in the scheme of things after spending £30 on guages, £200 + on an R134a cylinder etc.

 

Where it gets really expensive is the equipment to recover & recycle the existing regrigerant gases without creating your own personal hole in the ozone layer.

 

The camping gas style. I see what you mean about refilling without vacuum pumping first, your going to destroy your compressor.

 

Do you think this pump will do the job?

 

https://www.ebay.co.uk/itm/3CFM-1-3HP-Refrigerant-Rotary-Vane-Vacuum-Pump-A-C-Vacuum-Evacuation-Pump-UK/253448123586?epid=1949101799&_trkparms=ispr%3D1&hash=item3b02af74c2:g:fwIAAOSwRCZfz2-M&amdata=enc%3AAQAFAAACcBaobrjLl8XobRIiIML1V4Imu%2Fn%2BzU5L90Z278x5ickkrDx%2B2NLp21dg6hHbHAkGMWD%2BZ71uyMkBq%2BHgEC9Xcq30bR9b5wAxa8JG2KI8sc6GyS%2BhhguafGIbR0zOXOq7KQm985uRX7uyDk9lMECSrKWgQndJeGGPW8iLvH4HzMHpMg780WDUA02hi5OTEzvwK%2FiJDIKpK5YW%2FqwH740PzIA%2FYZ0wlJK7IFjM41L6phz7l9H403cTCh2RNekJ%2B2yw8tuwzHT%2B16%2BF369lgLDlRBp6KFti%2FY0TDsHDFT1ROkQDXIFs4cwLD%2FsrEOxBoMJaBUiTKTxRUJUTt2Ohohy9KCeBMRDySNIXxYqku3zy1t9jvJTOLfPcWZxAMwAKQRlRyuzzVQnA2AvirE%2Bxb%2BB2J3v%2FWq2a7AtNg5e2wWly207QaOxV8WsklMYNUROemTCWQwyc9mkpYhUG9vX0AxKD2JT6N46zxuB%2FKqH8oaz5%2FdUbxsrr437wQhT6RVUxDEpvdlIqoo0JwkzGty4fryd89NnNNbUdQsCotFixRIvQGL%2BQJO%2BpgHx2GxkGsd0KF6LJ9IaVo7Fi5Xut1nNRQIJVwS3BN28VMFj2eUWc3jTOFKjlfcXkSI4IRqbmtyHNgxOrABUejbRr4e3AsRZQCZGreJRrhltPY2fz705Oh2cvvEZjOisngVh5wNyM8dziofal8K7bmT%2BzvHVFvyGqE%2F95cbHS0xgNtXJxfgZMx4Irm5xtrLktkP1m%2BNvUYHmL5NpV0Y8X0r1TjTuLargVSA8tM70cJkw0AS9wnGScKJOfvnczyhgp5ZFB7YeNTvimhDBHNA%3D%3D|cksum%3A253448123586a7d1227675134049a7d6993befeb4010|ampid%3APL_CLK|clp%3A2334524

 

[J.R.]

That looks the same as mine which works OK, you will need to buy the special expensive oil that it uses as they are shipped dry, dont forget or you will destroy it straight away.

[Aj77]

1 minute ago, J.R. said:

That looks the same as mine which works OK, you will need to buy the special expensive oil that it uses as they are shipped dry, dont forget or you will destroy it straight away.

 

I read somewhere that you should keep the vacuum pump on for about 24hours can you confirm?

[J.R.]

Never heard of that.

 

Have you actually recieved your camping gas R134a? Are you planning on getting it from Ali-Express?

 

My first order was OK but there is a lot of wastage once the system has some pressure in it you can get less and less of the can contents into the system. All my subsequent orders never arrived, a lot of the listings did not actually have the regfrigerant when you clicked on them, just options for dye, oil, test kits etc, any that did sell it had to call it something else, basically I think it got shut down hence my move to a garage type cylinder which was loadsamoney but at least it keeps me away from the incompetent idiot robbers in the fastfit places around here.

[Aj77]

1 minute ago, J.R. said:

Never heard of that.

 

Have you actually recieved your camping gas R134a? Are you planning on getting it from Ali-Express?

 

My first order was OK but there is a lot of wastage once the system has some pressure in it you can get less and less of the can contents into the system. All my subsequent orders never arrived, a lot of the listings did not actually have the regfrigerant when you clicked on them, just options for dye, oil, test kits etc, any that did sell it had to call it something else, basically I think it got shut down hence my move to a garage type cylinder which was loadsamoney but at least it keeps me away from the incompetent idiot robbers in the fastfit places around here.

From https://www.thompsonsltd.co.uk/

 

I can't use it anyway until it's vacuumed. Well I can buy I risk damaging the compressor. It's tempting though to just fill it up and see what happens. The compressor has a thermal shut off switch.

[J.R.]

You could depress the Schrader valve with a pointed implement momentarily, if any gas comes out you have pressure in the system so no air contamination, you may have said you have VCDS, with that you can also check the high side pressure, be aware that it give absolute and not guage pressure.

 

You wont damage the compressor by turning on the AC without regfrigerant, if the low side does not have the minimum pressure then the climatronic controller will not command the solenoid valve, the pump turns all the time anyway, it will just continue stirring nothing but PAG oil.

[Aj77]

1 minute ago, J.R. said:

You could depress the Schrader valve with a pointed implement momentarily, if any gas comes out you have pressure in the system so no air contamination, you may have said you have VCDS, with that you can also check the high side pressure, be aware that it give absolute and not guage pressure.

 

You wont damage the compressor by turning on the AC without regfrigerant, if the low side does not have the minimum pressure then the climatronic controller will not command the solenoid valve, the pump turns all the time anyway, it will just continue stirring nothing but PAG oil.

But I was talking about if I filled the low side with the camping gas r134a I should be receiving tomorrow without vacuuming first.

 

I really doubt there's a molecule of Freon in the system as it hasn't blown cold air since about 9 months ago and when i bought the car the AC didn't blow cold air so who knows how long it's been like that.

[J.R.]

You could well be surprised, I repaired a written off Sierra (several actually) on one the aircon condensor was bent like a banana I was at the point of removing it when I had the instinct to press the valve first, it had pressure!!!

 

I had to do the repairs leaving it in situ, the aircon barely worked as the charge was insufficient but was fine when I had it recharged, the Fred in a shed back then had no more equipment than I did and did not vacuum it down.

 

The system will stop when the pressure drops beneath IIRC 2.7 bar absolute pressure, you could drive round for years like that before the natural losses leaked out everything.

 

OTOH if there is a leak you will be tearing it down anyway, its a £60 saving if you can delay buying the vacuum pump.

[Aj77]

5 minutes ago, J.R. said:

You could well be surprised, I repaired a written off Sierra (several actually) on one the aircon condensor was bent like a banana I was at the point of removing it when I had the instinct to press the valve first, it had pressure!!!

 

I had to do the repairs leaving it in situ, the aircon barely worked as the charge was insufficient but was fine when I had it recharged, the Fred in a shed back then had no more equipment than I did and did not vacuum it down.

 

The system will stop when the pressure drops beneath IIRC 2.7 bar absolute pressure, you could drive round for years like that before the natural losses leaked out everything.

 

OTOH if there is a leak you will be tearing it down anyway, its a £60 saving if you can delay buying the vacuum pump.

Good answer, you've convinced me to fill it, I'll press the L side depressor first.

[J.R.]

I would like to know what this non R134a non ozone depleting snake oil gas is especially as they claim a full charge can be done with one 168 gramme canister. I do hope its not Butane gas R600.

 

Please let us know how you get on