Metallic sound above 2500rpm when warmed up
 

Hi everyone. I've been driving a 2013 ttrs for a few years now. There is one issue that's been there almost from the start. The dealer service actually kept my car for 2 weeks and called in a specialist trying to find the cause and basically was unable. Fast forward to now, and while the problem has remained constant, my ability to ignore it has begun to diminish. So here's the deal:

Once my car is warmed up, then revving the engine above about 2500rpm will start to exhibit a kind of metallic whirring sound that becomes more pronounced until about 3500 rpm until the engine baseline noise friends it out. My ear in the cabin says the sound comes from the right side of the engine bay, but I know that is notoriously unreliable. It's almost like a grinding sound like if two metal discs were spinning against each other.

The car's mechanical checks and performance are seemingly unaffected.

Does anyone have any clue what this could be?

Thanks,

-Tanner