Radiator cracked: engine overheated: now I've got an intermittent clicking.

[curlykicker]

Yeah, that "click click click click click" that most of us know. I've used 3 quarts of Gunk's Valve Medic and it goes away but comes back intermittently. What additive should I try next? Add a 1/2 quart of ATF? Or the half quart of that Mystery Oil stuff? Or what? Any suggestions?

Or maybe I permanently damaged a valve from the overheating or something else. Any thoughts?

(The radiator, water pump, oil pump o-ring, and crank shaft seals have since been replaced.)