200k+ miles, 2012 Ford escape, 3.0 engine, not very well maintained honestly (just haven’t had the money so we’ve been slapping a bandaid on everything…)

Daily driver. Our AC seems to be leaking (hissing, no cold air) but thankfully summers over now! Well, now when we accelerate with the heat on, there’s a whirring/whining noise. It’s definitely noticable. It’s not there when we turn the fans completely off.

Even if it’s on 1 “bar” (which is barely on at all, can’t even hear the fans blowing) you can hear the whining kick up. But it’s only noticable when accelerating.

Hubby and I both are stumped. There’s nothing in common between the belt and heat system… is there? It just doesn’t make sense.

Will update soon with video link if I can pick up audio of it happening.