Shrill engine compartment sound

[TedMichon]

While coming down the 6000 feet elevation of Idyllwild CA this morning, our 2 month, 2000 mile old Bolt began making a shriil sound (like an aluminum fan blade in a metal cage hitting its cage,). This went on for 10 minutes and then stopped in a way that sounded like it was being turned off (!)!. Any other reports of shrill metallic sounds?

 

[SeanNelson]

While coming down the 6000 feet elevation of Idyllwild CA this morning, our 2 month, 2000 mile old Bolt began making a shriil sound (like an aluminum fan blade in a metal cage hitting its cage,). This went on for 10 minutes and then stopped in a way that sounded like it was being turned off (!)!. Any other reports of shrill metallic sounds?

While I haven't personally had this experience, I've seen a few posts now where this kind of thing has been attributed to a small rock getting wedged in between a disc brake rotor and its protective shield.

 

[TedMichon]

Thanks Sean, that sounds plausible.