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Discussion Starter #1
Hi,


My 2003 95 aero has AC - that's good. BUt, it really doesn't feel like it gets 'that' cold. It's been that way for the last two years, that I can recall. I just took it to my local tire/brake shop, and they checked and said that my refrigerant pressure was too high. So they replaced it, to the correct pressure. But, it still doesn't feel 'that' cold. Is there anything else to check?



Thanks
Mike
 

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The WIS (Workshop Information System) has a guide on how to check performance of a/c. I used a meat thermometer. ?



‘Murica conversions:
20-25C = 68-77F
50mm = 1.97 in.
7C = 44.6F
 

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Discussion Starter #5
Thanks for the replies. He did say that the lowest temp he got was 55 Fahrenheit, so yes, nowhere near the low temperature you mention.


No, no particular thought on why the pressure was too high. Said the pressure was ok now.


Could a faulty compressor in any way be at fault?


Thanks
Mike
 

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sitting there parked, with the a/c running for a while, how often do you hear the compressor click and cycle on and off?

how long does it stay on after it clicks before it clicks off again?

can you tell?
 

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I don't know a ton about AC but I've played with my car's AC a lot trying to get it to work right. I know from the WIS that the compressor high pressure cut off is set at 27-29 bar, which is 380-410psi psi. The compressor comes on when it's below about 24 bar, or 340 psi.

As I understand it these variable displacement compressors run at higher pressures and if the shop is used to seeing the standard low pressure around 30 and high pressure around 225-250 it's possible they underfilled it (unless they did it correctly, by weight). If you google normal AC pressures you'll get returns saying 250 psi or so, apparently that's too low on our cars. Maybe someone that knows more about this can chime in.
 

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A good way to diagnose blend door problems is to compare outlet temps on driver and passenger sides. It's usually the driver's side blend door that goes wonky so the passenger side outlet temps end up being lower.

In addition to the variable-displacement compressor, the 9-5 has a temprature-compensated expansion valve in front of the evaporator, not a fixed orifice tube. The TXV can get stuck open or blocked closed by debris or corrosion and is not too difficult or expensive to replace.

Charging and checking this system is a little more complicated than looking at high and low side pressures as they will change during operation.
 

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Discussion Starter #10
I listened to the compressor for a while this morning, and actually, I didn't get any cycle on/off clicks. I just googled this, and found this site:


https://www.fixmyoldride.com/car-AC-clutch-wont-engage.html


I'll spend some time going through this.


As far as error codes are concerned, I got '0' when I went through the test.


I'll also take a look at that expansion valve.



Thanks
Mike
 

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The 9-5 A/C system has to be charged by weight, not by any pressure readings. What the shop should have done is to evacuate the system, and then charge by weight, I think it's around 850g. So there's a good chance that it's not charged correctly at this point, no matter what other problems your system might have.



If the A/C is distinctly colder on the passenger side, then my experience is that it's a low charge.


Make sure it's properly charged. If that doesn't fix the problems, then it may be the blend doors. Having a Tech II to read the ACC data would be a big help here.
 

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The 9-5 A/C system has to be charged by weight, not by any pressure readings. What the shop should have done is to evacuate the system, and then charge by weight, I think it's around 850g. So there's a good chance that it's not charged correctly at this point, no matter what other problems your system might have.



If the A/C is distinctly colder on the passenger side, then my experience is that it's a low charge.


Make sure it's properly charged. If that doesn't fix the problems, then it may be the blend doors. Having a Tech II to read the ACC data would be a big help here.
+1 on this
 
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