Technical Low AC efficiency

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Technical Low AC efficiency

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Jul 28, 2018
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Hi, I have problem with manual AC on my JTD.
When I bought it, it didn't work at all. Then I changed the pressure sensor and AC started working, but temperature wasn't low enough. So I had it professionally recharged (there was 250 g, filled to 550 g), changed the filter, cleaned inside of the fan housing, but it still does not work as it should.
The air is cooler, so the AC is somehow working, but something is wrong.
Any ideas where to look?
 
First thing you should do is to make sure your ac compressor turns on.


Procedure:

1. Start car
2. Put temperature to the lowest
3. Press (enable) ac (snowflake icon)
4. Wait few minutes and look if ac compressor is turned on (starts rotating)
 
The air is cooler, so the AC is somehow working, but something is wrong.

You might need to be a bit more specific.

what temperatures are you operating in? do you have an all glass roof, are you running the aircon with the windows open. freshair or recirculated.

The fact that its working suggests there is nothing wrong with the system per say, so there has to be something else going on, things like the fins in the condensor being missing can have a big impact if more than a 1/3rd are gone, things like the cabin filter being completely blocked up will have a huge impact.
 
I am quite sure compressor kicks in - RPM goes up and air is cooler.
I turn it on when it's 28°C+, maximum outside temp is about 35°C. Air feels like 20-25°C (I will use some thermomether tommorow).
I don't have glass roof, new filer, recirculation on, windows closed (of course...)
 
Is it actually blowing enough air out? Pollen filter? Take it/them out (maybe two filters) cant remember and try the a/c again, cost nothing.
 
I had a problem with my AC which was blowing fresh air, not cold. Replaced the expasion valve and now is freezing cold. I even have to turn it off at night.
Also did a full A/C clean up, because i had too much oil in it and it could reduce the heat transfer in the evaporator and condenser; new oil and recharge 550g of freon.
I putted a thermometer inside the vents and at 32°C outside it gets down to 6-7°C.

What happens is that expasion valves could get stuck in one position and is not letting pass enough freon gas to the evaporator to cool it down.
 
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So for the third time: I have a new pollen filter (y). Fan is blowing strong.
This evening I checked the temperature at exhaust. It was 28°C outside, no direct sunlight, air recirculation on -> temp was 15°C. It is quite good, but when it's noon and the sun is heating whole car, it is not so great.
So how can I tell what is wrong with it?
Thanks for answers
 
So for the third time: I have a new pollen filter (y). Fan is blowing strong.
This evening I checked the temperature at exhaust. It was 28°C outside, no direct sunlight, air recirculation on -> temp was 15°C. It is quite good, but when it's noon and the sun is heating whole car, it is not so great.
So how can I tell what is wrong with it?
Thanks for answers

Have you checked the condition of the front condenser/Aircon red?
 
I've checked it now. It is not "brand new", but it looks fine - no visible damage or bent metal. About 6 months ago I removed bottom radiator holder and cleaned the space between two radiators. There was big load of leaves and stuff, but is should be clean now.
Also MES is showing only 0,039 bar of AC pressure. Is it normal? It showed this much before refill. The sensor is new (but cheap :D).
 
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