Troubleshooting AC not blowing cold after recharge and test

[Stamanatic]

Hi,

I got a hole in my condenser a few years ago but last week I finally replaced it, brought to a garage to recharge and lubricate everything.

It took them 2 hours before the compressor would run so it could take in the gas, they tested for the day and no leaks, but they said the pipes going into the compressor were red hot before, then after they finished finally, it took another hour of the engine running before the compressor would come on but it produced ice cold air. Then they came back and tried again and it went down to a couple of minutes before kicking in. Now it hasn't came on a few days.

I've done some testing in VCDS everything is looking okay, checked the fans in the engine output tests and they both come on, when I turn on the AC the small fan does not rotate but clearly it works.



Above are some measurement blocks, also looks fine to me.

What do you think a G65 pressure switch? Or an N280 solenoid valve that's on the compressor? Where can you see the compressor model, is it under the car and look up or top down?

[muff1991]

looks like your compressor isn’t running and it’s probably the solenoid or the compressor itself has had it. I think you have to remove the compressor to see the brand.


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[Stamanatic]

It ran eventually for the recharge and a few days after it would take 5 minutes to eventually get going, which makes me think it's the n28 solenoid valve, well hoping rather than the entire compressor, but it doesn't sound like a g65 issue does it?

[muff1991]

Mines been doing the same kinda thing, kicking in randomly and sometimes just won’t kick in at all. I think mines the solenoid valve too


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[pudding]

Can you feel/hear the compressor engaging?  It's quite a noticeable load on the engine when set to Auto and "LO" on the climate with full fan speed.

I'm hazarding a guess here, but as your A/C system had a hole in it for an extended period of time, it might have crud/corrosion in it. 

The oil infused refrigerant charge stops the corrosion attacking the compressor pistons.  If it's all leaked out over 3 years.....hmmm....I'm thinking it might be worth stripping the compressor down to refresh it with new seals etc, remove any water, corrosion etc and try again.  Try a new solenoid first though and see if it helps.

Or you could still have a leak somewhere.  Did the A/C engineers use a dye to check for that?   I know the MK5 A/C isn't the best but you should feel cold air within < 1 minute of driving.

[Stamanatic]

I can hear it engaging when it does blows cold, they tested it all day, as mentioned the compressor wouldn't turn on for hours to take the gas in.

it blew ice cold today for a long time, hours of driving, even stop starting throughout the day, pressed ECON to see if the compressor would work again after depressing ECON, it never came back on cold after that, just as I had thought might happen.

Here's a measuring block I took today when it was blowing cold, current is down and load has increased. Just seems as simple as it is not turning on, sounds very like the solenoid issues I see mentioned throughout.