I know A/C work is tricky and you have to know what your doing. I wanted to recharge my A/C the right way. I bought manifold gauges and a pump. The first attempt was a success. Hooked up the gauges and followed a pressure chart for the correct readings. I was low on Freon and i added a little bit and my A/C was perfect. I had 44 degrees coming out of the vents. Then my buddy said I didn't do it right and said I had to evac the system to do it right and prevent issues down the road.So i evaced the system and I've been having issues ever since. I put in 22.9oz according to the sticker on my car and both the low and high pressures were extremely high indicating an overcharge. So i had it discharged again and repeated the process but this time the low pressure was 35 and the high pressure was 150 and these are correct according to the temp outside but the high pressure needle was vibrating at 150 and the system still acted like it was overcharged. I released some of the Freon on the low side with a small screw driver but a lot of air came out and very little Freon. I decided to let all the Freon out and I had more air released than Freon. I had the system checked for leaks and I had none. I'm purging the line before I add Freon, so how is air getting in? I don't even know where to start. I should have never evaced anything, I had perfect A/C the first time I did this

 

You need to stop releasing that in the air. If you release a little bit there is no way to visually tell if it is air or freon coming out.
did you pull a vacuum on the entire system before refilling? If not there could be residual left when evacuating.
at this point there is no telling what is going on, perhaps debris moved in the system - it is just guessing frombthis time forward.

 

Yeah I don't know how you're discerning air from refrigerant when you discharge the system.

The correct way to do it is ensure there is sufficient oil in the system then pull a vacuum on the full system, then add the correct weight of refrigerant. If you know the weight of refrigerant in the system is correct and you are still getting high pressures (and the fans and compressor are cycling like they should), you likely have a blockage somewhere in the system.

 

Oxygen, nitrogen and refrigerant are colorless, odorless gases at room temperature and pressure.

 

I know releasing Freon into the air is bad, but when you have no A/C and a week to wait for an appointment to discharge it properly you're not going to wait. I just want my A/C fixed.

 

When I released a little bit of Freon it was air because nothing was on the white rag I was using.

 

Refrigerant will not leave a residue on a rag. When you see residue on a rag it is the oil and/or dye being pulled out of the system because you are discharging it too quickly. You will need to replace whatever oil you have blown out of the system. Insufficient oil can lead to compressor failure.

 

Just adding or topping off refrigerant doesn't usually require a full evacuation. Overall, it sounds like you did it right...however...when you say you "evac'd" the system, what does that mean? Did you actually pull vacuum on it for and long duration? Did you add or remove any PAG? Releasing the refrigerant thru the valve isn't really evacuating the system.

I advise that you get the system properly evacuated and that means a full vacuum. I'd let it pump down for at least 30-60 minutes. What I would do after that is pressurize the system with some dry nitrogen and record the pressure. Let the system sit with that nitrogen for a few hours WITHOUT your gauges on. Come back some time later and verify that your pressure is the same. If it is the same, then the system is leak free. If it isn't the same, you got issues to track down. (If you don't have access to nitrogen, just leave it under a vacuum WITHOUT the gauges on then come back and check if it still is holding a vacuum). Once you get the leaks fixed, if any, vacuum down the system again to get rid of the nitrogen (assuming you used it), if you didn't then go on then start the car, turn on the AC and start the charging on the low side. Use a scale to measure out weight and add it slowly.

You got to make sure you have the right amount of PAG in system. Hopefully, you didn't use remove any oil..too little causes problems...too much causes problems. Hopefully, you didn't use any R-134 can with an oil charge included.

 

I had my A/C discharged and I did a full vacuum with manifold gauges and a pump. I let it run for about 45 min. Didn't add any PAG oil because I haven't replaced anything. I already did the dry nitrogen and I don't have any leaks. Anyway I fixed it. When I got my system discharged I had way to much Freon and my system was filled with air. The tech asked how I filled the system. I told him I used regular Freon and turned the can upside down for a faster charge. Well I guess that wasn't a good idea on my car. Straight liquid into the A/C system isn't a good idea from what he told me. So when I redid it I just held the can upright and shook it a few times. It took longer to fill but I know have freezing cold A/C.