Could be...
More than likely the whistle came from the air port. Gunk on the coil probably lowered the velocity so that a harmonic oscillation set up on one of the hard edges in the air path.
PLEASE have pity on me! Are you funnin' with me again? What "hard edge?"
I'm getting confused here, so maybe I should just think of it as a "stoopid, change your wick" alarm and call it good!

