Re: MY12 Engine Harmonic Noise
I've never seen a 3.0 up close but it sure looks like a/c lines from what little I saw of them. Can you follow them to the a/c compressor, dryer, or where do they terminate? Can you post some more pictures of more of the line?
Whatever it is I would check all the bolts that mount those lines along their path (Incl. on the compressor or dryer if that's where they go). I see what looks like rubber isolators in the center of the picture. If so, check to see if the rubber has dry rotted or deteriorated to the point that they're not doing their job. Same with any others along the path of the lines.
It could also be the bearing in the a/c compressor (if that's where it goes) and holding the line changes the harmonics just enough to change the sound. (Kind of sounded like a spinning noise) That's probably a long shot though. Check the bolts holding the compressor to the engine. If it goes to the dryer, the bolts holding the dryer to the inner fenders or wherever it's located could be loose, allowing harmonics in the lines.