I bought a Blazer this summer with what was thought to be blown head gaskets. Had the head gasket job done and got the truck running, and had coolant in the oil again. We pulled the intake back off and noticed it was really pitted around one of the water jackets that looked like it could be leaking around the intake gasket. So we used rtv to fill the pitting and re assembled the motor. Before even starting the engine we added coolant and it took almost 3 gallons of coolant (from what ive read capacity is only 2 gal). then after starting, we had mixed coolant/oil again. Anyone have any ideas what the issue could be that would let the coolant into the oil before even running?

 

Maybe a crack in the block??
Just a guess.

 

thats what im thinking but im hoping theres something else i havent thought of