I have a 99 Legacy 2.2 L that's not cooling and has the following characteristics. No temp drop at vent, 65 psi low side and 125 psi high side with cool but not cold suction line at firewall. Changed with 12oz 134a and got 75 on low side, 135 on high side and warm suction line. Compressor or expansion valve or what ?

First let's determine if the refrigerant charge is in the ballpark. With the engine not running, measure the temperature and what both gauges are reading (allow the system to equalize), and let us know what you get.

89 degrees. 148 psi on low side and 150 psi on high side with engine off and sitting for 30 minutes. A/C not operated for at lease one week. From other posts it looks like a failed refrigerant control valve. What do you think ?

Edited June 29, 200916 yr by fixitguy50

89 degrees. 148 psi on low side and 150 psi on high side with engine off and sitting for 30 minutes. A/C not operated for at lease one week. From other posts it looks like a failed refrigerant control valve. What do you think ?

The static pressure is too high. Typically at 90 degrees F it should be between about 75 to 100 PSI. (A rough ''rule of thumb'' is static pressure in PSI equal to temp in degrees F.) The can of R134a that was added probably wasn't needed.

 

Based on your first post, with the system operating the low side pressure was too high, and the high side was too low. I agree with your thoughts that the compressor is bad or there's a control valve problem. R134a isn't an ozone-depleting gas -- however, since it is one that can contribute to climate change, it would be good to take the car to a pro who can recover the excess refrigerant and do a proper diagnosis.