About a year ago I had a anti freeze leak through the block around the upper cylinder area. Patched it. Now I'm the guy who just posted about a leaky manifold stud. My thoughts are these engines are 100 years old and some of these engines had coolant in them continually for 100 years. That coolant over time could have been well water, creek water, rain water, kerosene, or some mystery fluid. Now the metal of the engine is slowly rusting away and leaks are showing up in weird areas. THANKS to the guts who answered my stud problem

Depending on where the T has been, it cool have had a strong salt solution, for winter use.