Does anyone really know how automotive a/c works? | E46-chassis BMW M3

I had a similar problem with my previous (GE8) Honda Fit, though that was because road debris would pummel the low-mounted condenser.

My fix was to avoid driving it for an extended period–which worked well most of the time, actually.

I've got a pretty good understanding of ac systems and I don't think your symptoms line up with a properly charged system that was just evacd and recharged

Unless it tripped a digital bit in the car's body module when it was refilled, the service makes no sense.

I was never satisfied with the performance of the A/C in my E82. Even with a fresh recharge from my indy's fancy machine, it just didn't do what it should. There was clearly a very small leak somewhere, as performance degraded to the point that it didn't do much of anything about once a year. I finally bit the bullet this year and had the evaporator and the expansion valve replaced. That fixed it. The A/C now pumps consistently cold air the way it should. Not to say that's the situation with yours, but even if you don't want to do the evaporator, changing the expansion valve might be a quick and relatively cheap thing to try if performance degrades again.

Absolutely my least favorite DIY. Think I have worked on 4 vehicles of mine and to this day the rumor is I havent fixed a single one. 

DAMN that e46 reminds me of my old Avus e36. Loved that dang color.

NOHOME said:

Unless it tripped a digital bit in the car's body module when it was refilled, the service makes no sense.

I know. We're baffled as well.

And because we all love details.

Jesse's shop is half an hour away. Drove home with the a/c on and no problems.

Later that day, I had to run an errand–which happened to put me like around the corner from his shop. So, that was an hour in the car with cold a/c.

And then add in the minutes idling yesterday so I could take those pics of the thermometer. 

So far–fingers crossed–so good. 

I have a theory that the removed and replaced refrigerant is filtered during the time in the Mastercool rig. This has thus cleaned the orifice tube or expansion valve, which ever the car has. Or perhaps just re-positioned the offending debris, watch here for recurrent symptoms. 

In reply to TurnerX19 :

Thanks and, yeah, not a fan of a problem that magically clears up. But so far, after 90 minutes, we still have cold air.

Let's see if it holds. 

On a Monday I had AC in the R coming home from work, Tuesday AM nothing. Have not looked into it.

Hit nothing to knock a leak into the system. Thinking the clutch lost power or computer related.

Sucks when I need to defog.