While it looks like a crack, if I couldn't see it any better in person than in the pic, then I'd have to clean off the paint to make sure it isn't just a large area of paint about to flake off. Or a thick coating of paint that just cracked but the lug beneath is okay.
The little rust spot looks suspicious though. Is this some sort of one piece headset with lugs similar to the old Chicago Schwinn's with the eltroforged head tube? Maybe some poor welding and cleaning when it was made, but I guess if the bike is as old as it looks, the welds held up long enough. Let it go to the scrap yard to become something new.
Last edited by Iride01; 01-26-22 at 09:25 AM.