Auto Air Conditioning & Heater Repair: 1988 Chev Celebrity, psi readings, orifice tube

Question
Hello. My sister owns a 1988 Chev Celebrity. With 2.8 V6. Has been converted to R134a. I need to check her AC PSI readings. Do you have or at least know where I can find the correct Low and High readings?

Thanks.

Answer
Hi Chris,

 A retrofitted car like that with the original orifice tube will have slightly higher high side and slightly lower low side operating pressures.

Assuming ambient air temperature is 28 degrees Celcius or 80d F:

Static pressure (engine not running) 86-88psi
running pressure (engine running, compressor running) Low: 22-35 High 195-280

 If you are having difficulty with excessive compressor cycling you can install a variable orifice tube or better yet an adjustable low side pressure cycling switch.

Wayne

Sorry for late replies.  This is my busy season and its 40d Celcius outside.  I will get around to answering every question but it may take me a few hours. I typically book 12-15 cars a day right now and its getting overwhelming.  Many electrical problems and difficult to find leaks!