Phak1 In the olden days they had a sealant for chicken eggs that would make them keep better,it was a fairly thin liquid that would seal the egg shell. They also called it water glass. Enterprising mechanics learned to mix up a thicker concentration of that and use it to seal cracked blocks and valve seats. This was before permanent anti-freeze when they used methanol for anti-freeze. Prestone came in a 1 gallon rectanguler can that you used your curving oil stabber in the corner. There were many ways to administer crack repair,others will chime in .
