Black soot on the underside of the hood that looks a lot like a fan belt that is starting to fail. Five decades of wrenching on cruisers says further investigation required. Grab the fan blade. Yup. Half an hour later:
At least you caught it during a preventative inspection instead of out in the Mojave....
and decide how deeply down the ‘while you’re in there’ rabbit hole I want to go. Other than a few oil changes, I really haven’t been under the hood of this one much since