Sounds like a piece of plastic against a fan blade, or cards in bike spokes. Running fine though.
Happens when the car is idling/parked and becomes louder when accelerating.
Began hearing the sound much more quietly and intermittently prior to oil change in September. Over the last week (potentially more, it is hard to hear when driving with the AC/HEAT on so I may not have noticed) it has become very loud.
Seems to lessen when I maintain speed with no change in acceleration or deacceleration. Braking does not seem to lessen it, although I'm not yet 100% sure of that. Braking in neutral was no change; not sure of in motion.
White vapor-like smoke from tailpipe when accelerating. Disappears quickly. (possibly normal?)
Had oil and filter changed (was full at time of change) and tires rotated in September. Also replaced 2 tires in September. Replaced battery around September as well. Brake shoes and drums replaced last fall. Seems to be running fine besides the sound. Has always had a small power steering fluid leak (can't remember details but had it looked at once in 2013 and some work I don't remember done; it does alright if I just add power steering fluid every few months).
Had a check engine light on prior to battery replacement in August/September. Had it checked and the code ran something for oxygen sensor. Guy cleared the code for me and it showed once after, then never again. Had issues years ago (2013 or 2014) with it failing inspection due to oxygen sensor code/gas cap. Replaced the gas cap and passed inspection, was fine for several years.
Video of sound when parked: https://youtu.be/9nRsD50WXlA (open hood)
Video of accelerating in neutral: https://youtu.be/2thxJbKDM38 (closed hood)