O9 chevy aveo. Put on new expansion valve. Charged system blew cold for a minute. Then put on new compressor. Put in 1can oil and the 3 12 oz cans freon. Blew cold for a minute again and then hot.

the ac clutch is stayin on???right...

the ac clutch is stayin on???right... is there a vacuum leak??

Probably still too much freon and when the pressure increases the high pressure saftey works ... open the hood and see if the AC clutch disengauges. They put that switch in there because too many people were blowing the refrigerant lines in half and dumping 2 lbs of freon into the ozone layer ... or the line didn't blow in half and instead the compressor destroyed it self with bent rods

did you evacuate the system before you recharged it?

Rhodes ... realistically .. only a minuscule of people do that. They sell these 14 oz cans of 134a for < $15 bucks. Many people assume if 1 can gets you cool than 2 cans will get you cold. They don't know .. nor do they care how an AC works. Over the years this has been a boon to the Freon and Compressor manufacturers but has been a disaster to our Ozone layer. Have you ever seen the results of what happens to a compressor after someone inverts the can? The laws of Thermodynamics are proven when it states that "You cannot compress a liquid"

ya but if you don't evacuate the system and there is moister in the lines it will not work. it can freeze all so the size of your system is based on a vacuumed system so if it says 3.5 lb r134 it will only hold that if you get it evacuated to under 0 vacuum

True ,, and if the expansion valve were changed then the system was opened ... I wonder how he charged it with air in the system? BTW .. There is no "under 0 Hg " simply because 30" Hg is as good as it gets. No criticism because I thought the same thing until college (Engineering) . A vacuum is the absence of pressure .. once all the pressure is gone than it's gone and you can't go any further. Same as the fact that you can't make cold ... all you can do is take heat and move it somewhere else then what's remaining has no heat. Interesting concepts but the cornerstone of thermodynamics. Sorry for the yada,yada

lol but your gauge you buy is not an absolute pressure vacuum (pressure) which is a negative gauge pressure and referenced to the surrounding atmosphere. there for a Gauge pressure is zero-referenced against ambient air pressure, so it is equal to absolute pressure minus atmospheric pressure. Negative signs are usually omitted. no collage for that one lol

in other words you will see a negative on the interments you buy for auto ac how ever no such thing as vacuum just an absence of pressure but for us to read it there it is below 0 lol