I have had some similar intermittent symptoms/sounds, but the a/c never quits working.I posted under the Problems & Maintenance section regarding an ongoing problem I'm having with my A/C; however, I wanted to know if anyone with a 3rd gen Outback has had similar issues.
Here's the problem: I go my 08 XT brand new in Dec 2007. Every summer since, my A/C craps out towards the end of summer. Usually sometime between July and mid-Sept. The problem begins initially by the A/C blower motor making noise (I equate it to the sound of a baseball card in bicycle spokes). Then, the output becomes sporadic before the blower quits. However, the blower does not quit completely. It will cease to work for maybe a day or two and then start working again. The process repeats a few time before it dies all together.
I have been told it was originally just a faulty blower motor. Then, the resistor blew out the blower so both were replaced. In 2010, I was told a short was found in the audio-a/c master control and that was replaced. Last year, I was told it was a clogged condensation drain from the compressor (which I have research and I should have had water on the passenger floor, which I did not). Also, I would figure water would short it out completely, not cause it to work intermittently. It is starting to go on the fritz again, of course when I to it to the dealer last week, it was working and they of course want me to bring it back when it is not.
Sorry for the long post but, I want to provide some background. Hoping there is someone who has had a similar problem and found a solution. Thanks for listening.
For me, the "baseball card in bicycle spokes" sound is noticeable when I turn the car off (with the a/c on auto) - the sound comes from the middle of the dash. Somewhat of a "clicking" sound.
Oddly, a few months ago, I had a chirping sound (like a small bird) when the a/c was running through the vent fans. The sound would disappear when I directed the air to the defrost or under the dash. This drove me nuts for a couple of days, then went away entirely.
I believe this may be a blend door that's sticky (or needs replacing) - possibly causing both noises.