If you run pure evaporust instead of coolant for a few months
It slowly dissolves the old stop leak and the evaporust will turn as black as used oil. Repeat as needed.
After I did this procedure to one of my 53 trucks the engine no longer overheated and the coolant stays looking bright green.
However evaporust to fill the coolant system isn’t cheap
and two treatments might be on par for a replacement used radiator.
-s
Do you know what the active ingredients are in evaporust? Some kind of acid?
