I have exactly the same issue on my 3100 235 block.
Lower left just aft of the manifold
Little pipe comes out the side of the block near this leak.....don't know what the pipe is for.
Seems the leak is a little higher up
Prob 2 inch crack
Looks like is an old crack as the block is rusty below and aft,of the crack.
Some JB weld on order and some K seal radiator/block sealer
The area is a bit hard to get to.....just Gotta do what I can I guess to clean it all off before applying the JB weld
Thought I had nearly finished the refurb.....
But hey, wasn't to be I guess.
Philip
