2001 Nubira Air Conditioning

[Rob916]

I have a 2001 Nubira that I recently acquired. The A/C does not blow cold. I can turn it on, the AC light illuminates, the compressor kicks on and stays on yet it does not cool. I checked the low side pressure and it stays at about 80psi so I did not try and put any more 134a into the system. Does anyone have any idea what it could be on this car? I am not too terribly familiar with the AC system on the Daewoo vehicles.

[Daniel]

You may have a defective control valve on compressor. Ask Google "Decreased Cooling In GM And VW Cars" for further details.
But it's not a DIY job as you must recover fluids before opening circuit.

[woo99SE]

if the ac compressor was OFF when you saw the 80psi it still low on gas.
that is low head pressure(comp. off)

if the comp. was turning when you saw that 80psi then something is clogged up. and yes don't put more refrigerant in the system.

[Rob916]

Ok so a friend of mine had some manifold gauges so we hooked them up to get a better idea of what is going on. With the engine off the low side was pretty high, the high side was approximately 140 psi. I started the engine and the low side pressure dropped to approximately 75-85 psi and the high side stayed at approximately 140 psi. The temperature outside was about 85F degrees (29 degrees Celsius). We hosed the condenser down with it running and the high side pressure dropped a little. My friend says it seems like the expansion valve is stuck. I'm pretty clueless about the whole thing, would the refrigerant control valve being bad cause the same symptoms?

[Daniel]

With the engine off the low side was pretty high, the high side was approximately 140 psi.

You should find same pressures both sides depending of temprature. Here ~95psi. See chart.

Pressure Temp chart.JPG

I started the engine and the low side pressure dropped to approximately 75-85 psi and the high side stayed at approximately 140 psi.

Should have been dropped to 30~35psi and raised to ~200psi. See chart.

AC performance test.JPG

I'm not a refrigerant specialist but IMHO if the expansion valve was stuck closed the low side should have been lower and the high side higher that what you have measured with engine running.
Looks to me that the expansion valve is stuck open. But I can be wrong. Take further advices.

air_conditioning.jpg

[MMamdouh]

as long as your gas pressure is right...it will be this damn valve:



it is on the underside of the compressor and you will have to vacuum and recharge the system after replacing it

MMamdouh

[Rob916]

Excellent.. Thanks for posting the part number. I went to my local Chevy dealer and they were able to order it for me. Part is cheap enough to give it a try. A friend of mine has everything we need to recharge the system including a 30lb cylinder of 134a so I hope to be up and running next weekend! I can only handle 100F+ temperatures for so long.

[benzino]

try summer in australia without a/c

[Daniel]

as long as your gas pressure is right...it will be this damn valve:



it is on the underside of the compressor and you will have to vacuum and recharge the system after replacing it

MMamdouh

Big bump.
Here is how those valves fail https://youtu.be/hl41q5o6XLo . Pierced bellows not allowing valve to close passages and compressor stroke stays at minimum.

Edit:
BTW the control valve may have different working pressure, same shape. They are colour coded on the tip. Mine is a "yellow" one on my Nubira.