Air con headache

[Keefy]

Hi all. I've been trying to fix this for a while now with no joy. Searching the forum doesn't really answer it either so I thought I'd start a thread.

My air con stopped blowing cold a few months back, and I assumed it needed a re-gas. I asked my local trusted VAG specialist to do this at the same time as the service and MOT last week. Unfortunately the garage said they couldn't get it working and that I should get in touch with an aircon specialist. A few days later, I booked it in with an aircon shop, who also couldn't find the issue. The compressor kicks in, it's full of gas, and the only thing they could think of was that it might be the expansion valve.

Has anyone else had issues and replaced it? Am I right in thinking it's a PITA to get to?

Cheers.

 

[S3AMJ]

Hi all. I've been trying to fix this for a while now with no joy. Searching the forum doesn't really answer it either so I thought I'd start a thread.

My air con stopped blowing cold a few months back, and I assumed it needed a re-gas. I asked my local trusted VAG specialist to do this at the same time as the service and MOT last week. Unfortunately the garage said they couldn't get it working and that I should get in touch with an aircon specialist. A few days later, I booked it in with an aircon shop, who also couldn't find the issue. The compressor kicks in, it's full of gas, and the only thing they could think of was that it might be the expansion valve.

Has anyone else had issues and replaced it? Am I right in thinking it's a PITA to get to?

Cheers.

Hi dude, have you checked for any codes. If it’s a pressure switch then it should come up with a code. Do you have access to VCDS?


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[Keefy]

Hi dude, have you checked for any codes. If it’s a pressure switch then it should come up with a code. Do you have access to VCDS?


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I don't unfortunately. The aircon guys plugged it in and couldn't find anything unusual.
Baffled.

 

[S3AMJ]

The air con guys scanned the car for faults. Does seem odd..... did they flush the system out incase of blockages, etc. Run the car with the aircon on and feel the pipes coming out of the compressor one should be hot (super heat) and one should be cold (sub cooled).


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[Keefy]

Due to Covid precautions I couldn't be in there while they were working, so not exactly sure what they did but, they had ran it for a good while and spent ages fiddling around with their laptop.
I'm pretty clueless when it comes to a/c and where all the bits are. Is the expansion valve unlikely to be the culprit dyou think?

 

[S3AMJ]

The expansion valve is what regulates the refrigerant, if this has failed and it’s shut then the refrigerant can’t pass through to be cooled. But they would have checked that if they had anything about them. Run the car with the aircon on and feel the two pipes, one will be going in which should be cold, the other coming out should be hot.

Alternatively follow the pipework as best you can and see where the valve is. I need to replace my pressure switch at some point. But that’s different to your issue, my aircon compressor cuts out as soon as you turn it on. Yours is running isn’t it?


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[Keefy]

Yeah it's running. All seems completely normal (slight drop in revs when i switch from econ to a/c) and nothing seems different to 4 months ago, other than it's just blowing cold.
TBH i wouldn't even know which pipework to follow - the idea of feeling pipes on a running engine doesn't appeal to me TBH! Might just have to try another aircon specialist. Thanks for the response tho

 

[S3AMJ]

There will be two pipes side by side going into the bulkhead, one larger diameter pipe which is your low side... (cold) and the smaller diameter pipe is your high side (warm-hot) pretty safe to feel yourself.

If in doubt take it to another specialist.


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[Keefy]

Yeah I don't even know which side of the engine bay I should be looking at
I guess I'm just trying to work out if it's worth getting it looked at. Happy to spend £1-200 to sort but if it's going to be a day's labour to remove half the engine to get to the bulkead then I might just not bother and live without a/c

 

[S3AMJ]

You won’t need to go to those extremes haha...


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