My AC went from working one day to not cooling the next. At first it seemed like the common Tstat problem but I have ruled that out. Here are the syptoms if anyone could help diagnos the problem. When you first crank the car sometimes the AC works good till you start driving it. Then cool air goes away. The AC clutch is engaging and compressor working when its blowing cold and when its blowing warm. Clutch is still engaged. With AC gauges on it and when its cooling the low side is at about 45-50 and the high side is at about 190. When the AC quits cooling the Low side will climb to 90 and high side is staying at around the 190 on the pressure gages.


One of my questions is Are the compressors on the HHR a Variable displacement compressor??


If so I am starting to think that the control valve is sticking not letting the Freon pass and raising pressure on the low side.


Any advice or ideas would be appreciated. Ive only had this 2009 HHR for 4 months so I havnt really got to really look over what all is on the car as far as type compressor and the workings of it. I have read about the Tstat issue not letting the AC work but my gauge is working fine and digital readout working also and temps are staying between 190-195.

 

You know more about A/C than I do. Here is the pressure chart:

 

Welcome to the site.

The high side does appear to have low pressure. Have you tried adding any freon ? Maybe add 1/2 lb or so to get the pressure up and see if that helps.

 

Yesterday I did add just a bit to see if there was any change and all it was doing was raising my low pressure up. I was pretty sure it wasn't low just because it was ice cold the night before and wasn't working the next day when I got back in it But I did add a little just to test it to see. My latest readings this afternoon the high side has come up some but so has the outside temperature. It was at about 225

 

Still havn't figured this one out. Its been working fine for a few weeks and today it started blowing warm air again. Still wondering if the Freon control valve in the compressor is getting stuck. Has Anyone ever had to replace that valve in the compressor?????

 

Refrigerant Pressure valves have been known to malfunction, even more if somebody pumped stop leak into it.

 

Thermostat should be a 180 degree AC Delco thermostat, perhaps the 190 degree is a little to high as the stat is either incorrect is sticking closed for to long and hasn't set a code!
It would be a P0128 , it could also be the 2009 HHR, has not had its thermostat replaced or the Dexcool replaced, it really is only good for 5 years!

 

Its been a little over 2 years since I made this post. The Ac corrected itself and has been fine ever since. Still making me think the control valve was sticking. Last week the exact same problem is back. Ac works perfect at times and then will go hot. Some days it works some days it doesn't. Since its been two years just wondering if any one else has had this issue or if anyone has any more info. I hate to just install a new compressor without knowing for sure whats going on with it.

 

Why not replace the pressure switch if you think it sticks?

If the engine does not warm to 180F fast enough the AC will not run. There may be a pending P0128 code, that would not trigger the CEL. Does the engine temp run less than 180F?

The AC is very simple; when you push the button the compressor turns on unless the pressure switch senses too high or too low. I don't know what other switch you may be expecting to see.

 

Your diagnosis may be correct.
Sounds like your expansion valve is acting up. It's not in the compressor.
It's really best to flush and then add correct amount of oil and refrigerant if you decide to change it.
Give it a couple of little wacks and see if it cures it to be sure.
You may also just be overcharged too.

https://www.autozone.com/cooling-hea.../444474_8581_0