I was one of those FB posters. I started hearing the high pitched noise about 2 weeks ago. This past weekend my fan must have failed because my engine overheated while idling with AC on. Anyone hearing that high pitched noise may want to test their fan by leaving X idling in drive with AC on Max. When I did this, with temp 80+ outside, it only took about 5 minutes for engine to almost reach max temp.
Dealer told me yesterday he was having a fan sent overnight to the dealer. I think I'll be calling today to make sure it was not back-ordered.