You are not gonna like this...If you put a bolt that was too long in the front cover it will go through the open coolant passage and punch a hole/crack on the inside of the passage letting water go right into the crank case. It is actually a thin wall of metal separating the coolant from the crank case. If you run too long of a bolt and torque it down it will punch a hole or crack that inside wall. If you can find the spot you can JB weld it closed. It is not a stressed location in the block.
