I'm thinking about using K&W for block sealer.
I have too hair line cracks below and half way between my block deck and oil pan. So they are pretty much in the middle.
K&W block sealer? Hows it work?
I tried to JB weld but it didnt hold.
The blocks cast iron.

 

not likely that stuff will hold either.

The obvious fix is to do it right the first time and replace the block.

 

If that junk is supposed to seal the block... imagine what it's doing to the oil passages.

I'd never trust a mechanic in a bottle.

I'm with Coug, replace the block.