Yep, that tank is a goner! Once those stress cracks form, there's virtually no way to keep them from spreading, same thing with a gas tank that develops a crack. If someone with a radiator with a trashed core wants to donate a top tank to you, that's about the only way to put that one back into service.
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!