A friend of mine was working on truck had to replace freeze plug by starter had hard time getting started out there is a small it's not visible crack in the block only know it's there when the water comes out they are now wondering if maybe they hit to the hard on the block or two sharply with the flat screwdriver on the Block and cause this invisible slight crack on the block which is said would it have been possible for them to hit the block and cause to crack which mind's eye looks like a paper cut