[Jammy]

I dont wanna be that guy but... That looks like a crack that goes into your coolant galleries inside your engine, clean it off if with some scotch brite or sand paper (if you can reach it). its hard to tell in the photos but it could just be a leak dripping from above or being flung off of the lower pulleys into that corner. If it is a crack, depending on how OCD you are and how hard the fix is it might just be worth it to leave it and keep an eye on your coolant. The only other fix would be to pull the engine and have it welded. Taste it and let us know LOL

 

[Jammy]

It's coolant being flung up and all over the place by the water pump pulley.
You can see the vacuum nipple for the water pump shroud right below it, and you can see the coolant on the ground in his 2nd pic.

savage knows more about this engine, ignore my previous post.