I wanted to update this thread to add a resolution to this issue. I decided to go with the GM tablets as a first attempt. I dropped 3 tabs in the radiator and let my truck idle up to temp. Directions call for adding the tabs with new coolant. I just put new coolant in it two weeks ago when I swapped the radiator, so I figured it was still "new". After warming up, I saw only the slightest hint of moisture coming from the crack. Next, I went for a 30 minute drive and then let the truck cool down. After subsequent drives I have not seen any coolant whatsoever. It appears that these tablets have done the trick, at least for now!
