Knocking and grinding, part II...
 

I was able to get a better view from the side and with the engine running, the crankshaft pulley misses the fan shroud by 1 or 2 mm.

The knocking appears to be coming from the crankshaft pulley bearings or maybe the crankshaft itself. This morning, the knocking briefly turned into a terrible grinding for about 5 seconds. Before and after, the motor runs strong.

Any ideas? Do I drive or do I tow my car to the shop? Thanks.

Does the noise occur when idling? Is there any visible 'wobble' or runout at the edge of the crank pulley?

Just to be sure ... and eliminate all things external to the pulley ... remove the A/C belt, and see if there is any difference.

If the M12 bolt for the crank pulley were loose, it might be your 'noise' problem. To check that the muffler needs to come off. Support rear of engine with jack... then, remove rear support and crossmember.

Thanks. The knocking is present at idle, with or without belts attached.
Guess I'll hobble into the shop and let the professional have a look.