Trying to diagnose the AC no longer pushing cold air out of an R56 MCS. When I turn on the AC, there's a hissing noise, of sorts, that comes out from the passenger side, feels like it's on the inside more than on the outside. What should I be looking at, as far as diagnosing it? Things I've checked:

- Bavtech scan showed nothing
- I've read about lowered suspensions and broken AC lines. I took off my right wheel, verified the metal pipe: it does have some rubbing on it, but it's not rubbed to the point of leaking
- Pressing the AC button does change the load on the engine, so I think the compressor is working?

I can't seem to get into the IHKA diagnostic mode to check anything. I also don't have any other leads for now. I do have an INPA cable and a Bavtech cable, if that would be of use to look for errors.

Any thoughts, anyone? Thanks!

 

a little too late to chip in, but did you check the pressure in the system. charge it and see what happens.

 

This one we finally figured out - cheers. We put ink in the system, flushed it and ran it for a few weeks. Turns out there was a really, really, really tiny leak in one of the hose bends; we decided to leave it as is for now, because it was too much hassle to take apart the whole front to reach it, and the leak was minuscule (i.e. it probably took a few years to leak originally). So for now, we refilled the system and it's been fine for a year; now that I'm fixing that oil leak at the same time, I'm probably going to have the pipe either aluminium-welded, or just replace it.