AC airflow stops blowing

[Bayerische415]

I have a 2013 F30 with 44,000. About 2 months ago my wife and I were driving a 5 hour trip home, and by the time we got home there was little to no AC air coming out of the vents. The blower was "working" we could hear the sound of air being blown somewhere, but not out of any of the vents. The next day, it was fine and I didn't have any problems until yesterday. Once again, we were making a 5-6 hour drive home and the airflow got progressively worse to the point that I had the blower on high and we were getting just a trickle of cool air. We stopped for a bite and by the time we came out (probably 30 min) and started the car again, it was working. About 2 hours down the road, I realized I was getting hot and turned the fan up to realize the airflow was gone again. We spent the last hour in the car sweating. By the time we reached our destination, again the blower was on high and there was just a tiny trickle of cold air. I tried to change all kinds of settings just to try to make it do something. At this point, when I turned off the "max a/c" - the what little airflow we had would stop coming out of the vents and the air sound changed drastically. The vent selector was still positioned to the main upper front vents.

It seems to me that this could be a vacuum issue with whatever mechanism causes the air flow to be directed to the selected vents. The car is still under warranty, but I'm not going to be able to make it reproduce the problem. Any advice on this would be appreciated and any advice on how to more correctly describe to my service shop would be helpful as well.

[2013f30]

Hey! I have the same car, same year, and I am having this EXACT same issue. Did you ever figure out what was wrong?

[marvinstockman]

If the evaporator is freezing up, it will block airflow thru the system. When it happens turn off the AC, but leave the fan on. It will unfreeze, and air should start flowing again. You can then the AC back on.

There is a sensor on the evaporator to prevent freezing, which may be bad. Should be covered by your warranty.

[2013f30]

Thank you! I did more online research and came to the same conclusion.

[White94RX]

Definitely sounds like the evap is freezing. There's a BMW service bulletin about it. The car may need the temp sensor replaced for the evap, but I'm pretty sure there's a programming "conversion" to raise the evap temp by 1 or 2 degrees that stops it from freezing.

[SlackTube]

Sensor does not get replaced and is not faulty. The sensor gets a spacer installed OR the vehicle needs programmed.
other than that the forum is most likey correct about the evap freezing

[White94RX]

Ahh, yes, I think your are correct now that I think about it. There was an older car that would get the sensor replaced. E90 maybe? I can't remember.

[SlackTube]

I don't recall any evap sensors being replaced on E9x vehicles but I could be wrong. I know that the evaporators are junk on E90 and reguardless of Valeo or Denso they leak. There is a current SIB on this but that another subject entirely