Bighig

I'm having the exact same sound now. A few months ago I noticed a horrible grinding sound upon cold start up, which ended up being a bad fan clutch and idler. Had them replaced at the dealer ($$$) and then noticed this sound. Looks like I got one out of the bad batch.

It's only there when it high idles, so yes, when it returns to regular idle RPM.

Hey guys! First post, I'm sure I did it wrong, move me if needed! Long time stalker here. Normally I some poor soul has had to deal with my issue and fixed it, but I can't quite find what exactly is going on through any forum I've seen. Today I got up for work and remote started my truck. It ran for about 5 min before I went out to push snow off. It was about 30 degrees out. It was high idling the whole time. I then heard a very obvious groaning sound coming from the front of the engine bay, toward the fan and shroud as far as I can tell. Kinda sounds like a lawn mower or leaf blower on the videos I took and is less obvious than it is in person.Something vibrating or rubbing? I only hear it at idle outside the truck. It either doesn't happen or isn't loud enough while driving. Can sort of here it in the cab while idling. Any ideas? Stopped by the local diesel shop and they've never heard it before. https://youtu.be/fu2WAYbbfSc?feature=shared