So, initially, my timing chain snapped years ago, causing me to have to replace it and my head. Has nothing to really do with it, but it sat for some time, like almost two years or so, before I actually got around to repairing it. When I did, the AC blew warm. I had already got a new car like a month after the timing chain snapped, so I was in no rush to look into the AC issue. It is a 2007 Saturn Ion-2 2.2 by the way

At one point, years later, my new cars AC started blowing warm. Long story short, I found a mechanic who wasn't trying to play me by making me believe the whole system needed to be replaced. Evacuated and recharged the system, and my ac blows cold til this day, going on the second year, although the dye he put in it shows there is a very slow leak somewhere, unfortunately

I took the Saturn to him, and he did the same thing, and the AC was blowing cold again. I don't remember if he added dye to it tho. AC worked fine for months and months, and then one day, it stopped. I figured it had a slow leak somewhere. The next day, I drove it, it was back blowing cold and then eventually stopped again. I found that after the car has been parked for some time, and on cold starts, the AC would be back working again, but only for an hour to an hour and a half then shut off. I never found out why but I figured it ran low again because of the "slow leak", so I tried to self diagnose it using a manifold gauge and eventually decided to try and add refrigerant to the system sincethe psi was low on both low side and high side. This was a mistake, I guess. I heard a sound that resembled an air compressor when if gets the point of building up mac pressure, except not as loud and the hiss lasted a lot longer like when air runs completely out of a tire, gradually hissing less and less until all air is out.

Now the ac won't blow cold at all. Did it over-pressurize? Before I attempted to add refrigerant, I pushed a screwdriver inside the schrader valve to release pressure from the system, so I'm not sure what happened.

Now fast forward to a few days ago. I had a guy who says he has certificates or degrees or whatever" diagnose" the system. He works on a lot of people cars outside of a nearby Autozone. He's a mobile mechanic with a work van. He hooked up a single gauge to the high pressure line and said it was empty and that I needed to go in and purchase a can of refrigerant. He added the refrigerant and pointed out that the clutch wasn't engaging and said I needed a new compressor. The line line got really cold as he was adding refrigerant. He only attempted to add a little. I still have the 8oz can, which seems like it's still kinda full. When I tried adding it a long time ago, the line never got cold at all, yet all the freon emptied from the can!

My question is, how can he tell that the compressor needs to be replaced? A few days later, I hooked my scanner tool up to the OBDII port and found that there is a feature that allows for activating the compressor. When I click "on," the clutch engages, but only for a few seconds. I'm assuming it's because it's designed to turn off due to low pressure from a leak or whatever to protect the compressor, correct? I honestly think I messed it up trying to add

Please share thoughts. Thanks

 

Take the serp belt off and spin by hand the AC pulley. Does it spin freely?

 

I forgot to mention that I attempted to spin the clutch by hand and it spins freely. The serpentine belt needs to be removed when spinning it? Or I need to spin the compressor pulley itself?

 

Scratch that. I'm heading off in the wrong direction I think. I'm going to leave this one to someone else

 

Just came to me while changing trans fluid in my A3.

He hooked up a gauge to the low side port, not the high side port. If it was only a single gauge, that's what he did. He probably looked for the pressure on the low side, noted what it was, then turned the AC on. If it ran long enough with the clutch kicked in, what he should have seen was the low side pressure drop. This would indicate some level of compression in the system. I'm assuming he saw no change whatsoever with the compressor running. As such, he proclaimed that you need a new compressor.

Assumptions he made are that because the system actually ran, he had put in enough refrigerant to have the pressure be above the low pressure cut off. Therefore if it's running and not compressing you need a new compressor.

even if you have a leak in the system, if it is quasi-sealed there should be some sign of compression occurring no matter how small.

By the time you checked it with your tool and turned it on, whatever refrigerant he had put in had leaked out, the low cutoff switch or equivalent had shut off the compressor.

I'm not sure how AC in ions works. It has a BCM, so the request for clutch engagement goes likely to the BCM which closes a circuit to ground to complete the circuit for the compressor clutch. It may be that the low pressure switch does not directly interrupt voltage to the compressor clutch when it triggers. It may send a signal to the BCM and then the BCM maybe changing the state of a relay. Don't know, but someone else does. That's the only way I can think of you being able to have the compressor kick on for a few seconds. Because if the low pressure cut off switch was directly in the circuit in series, once it opened you would not be able to get voltage / current to the clutch

 

I had been wanting to go back to that guy and show him that I was able to get the clutch to engage and spin using my scanner tool, but recently it had stopped detecting the engine and transmission. Reads everything else. I thought it was due to me bumping into the scanner while it was plugged in, but yesterday I found that one of the pins on the scanner was bent. I bent it back into place as best I could, but the scanner now sits loosely, so if I'm not holding it in place a certain way, it won't power on. I might have to replace the port.

Anyway, before I figured out the scanner/port issue, I went to see the guy and told him I was able to get the compressor to come on. He said that was impossible. I told him I'd show him once I fixed my scanner port, and he told me to come back and show him. He explained what he had already explained before and said if I had some refrigerant, he'd show me in his gauge. I had some from the last time we met and gave it to him. He hooked up his gauge, and as he added some, he noticed the clutch spinning and kept adding, showing me his gauge, and it was in the red. I think I remember it being low the last time. He is trying to convince me that the compressor is bad.

I think the clutch had stopped spinning at some point. Suddenly, there is a loud pop sound, similar to a balloon popping but amplified. He goes, "BOOM, see, I told you." I asked him what the hell that was. I forget what he said, but basically that my compressor was bad. I look down at the compressor, and the clutch is spinning. The AC line is not cold.

Any clue on what he caused to happen? He acted kind of careless and sort of casually walked off after vaguely explaining. I should have taken it to someone else once I saw that the compressor clutch was able to spin before.

Thanks.