Which news do you want first the "good" or the "BAD"? The good news is if you had changed the thermostat from the start you wouldn't be having the issue your are now.
The bad news: the stop leak shit kills engines. (they need to ban that shit!) That stuff blocks and clogs passages that need to be open which is one of the reasons you are over heating.
The only cure for a leak is to address whats causing it. At this point all you can do is try and flush that garbage out and pray that what ever it blocked comes unclogged.
Also replace the thermostat with an OEM not parts store unit and "pray for the best."
The bad news: the stop leak shit kills engines. (they need to ban that shit!) That stuff blocks and clogs passages that need to be open which is one of the reasons you are over heating.
The only cure for a leak is to address whats causing it. At this point all you can do is try and flush that garbage out and pray that what ever it blocked comes unclogged.
Also replace the thermostat with an OEM not parts store unit and "pray for the best."