Compressor sometimes stalls engine - Mazda 3 2008

[ivangobike]

Hello!
2008 Mazda 3 sedan 2.0L automatic.
258,000 km (160,000 miles).
Climate: Rainforest climate with a few weeks of snowy winters.

Car was totaled to ICBC by previous owner in April 2022. I purchased the car that same month through a friend who owns a body shop straight from ICBC.

The AC system ran well before we rebuilt the car, replacing the condenser with a new one in the process yet not charging it with fresh freon. The compressor had 0PSI in it, and therefore never would turn on as I drove it regularly from September 2022 until March 2023, at which point I parked it for another 3 months to make general repairs on it myself.

1 month ago I started driving it again, and less than 2 weeks ago I charged the system to 35PSI and it worked great for a week. In hindsight I now realize the compressor was definitely rattling a little loud when it would turn on but worked well.

3 days ago I noticed that the compressor would cycle on and off while I had air blowing on, even without the ac turned on (I assume this is the behaviour it exhibits in high humidity? It was raining for 2 days then) (perhaps I noticed this only because the noise the compressor would make when it was kicking on was getting greater).

The next day, which is the day before yesterday, while waiting in a McDonald's drive thru the compressor made a strong rattle/click sound when it turned on, almost stalling the engine. About 1 minute later it did it again. I immediately removed the AC relay, disabling the AC clutch from kicking on.

Once home, I tested a bit to see what was going on, and the loud sound would occur most of the time now while also almost stalling the engine, and a few times actually did stall the engine! I then pressure-tested the system, which gave normal 35PSI on the low side (which would creep up above 200PSI upon the compressor turning off).

I took out some of the freon to lower the PSI and thereby lower the load on the compressor, and while this did reduce the noise the compressor was making when it turned on, it no longer blew cold air when I had AC turned on. I then had the system completely emptied of freon and removed the compressor. While still pressurized i could easily turn it by hand while also feeling the friction expected of the gas it would push within. Now with it out of the car, turning it by hand is super easy and smooth.

And that's as much as I know. Do I need a new compressor? Can I have my own rebuilt? Should I have my system tested for clogs or something?

Any help would be appreciated! Thanks

[tbirdtbird]

The compressor has grenaded and simultaneously sent shrapnel to your new condenser and probably beyond. The fact that it now turns freely has no meaning.
You need a new comp (rebuilts do not hold up), new condenser, and the hose that runs from the condenser to the evaporator (that is where the orifice tube {OT} will be and it will be clogged with trash), and new OT.
I think I would also replace the accumulator and see if you can get the evap professionally flushed.

Charging to 35 psi would not be the way any of us or the factory would do it. There should be a sticker under the hood that tells what weight of 134 to install. You will need a new oil charge,
New comps come with oil but it may be shipping oil. Best to dump out the oil that is in there, while rotating the shaft several times to get it all out. Measure how much you get out. Determine which type and weight of oil is needed (from the label on the comp), and install that into the comp while again rotating the shaft a dozen times. We never assume the comp has the correct oil.

[ivangobike]

Ugh...OK. I'll figure things out from here then, thanks!