I am having a very small leak at manifold stud #1 (closest to the water pump). The water isn't running out, but rater boiling off on the end of the stud when the engine is running.
I looked back through my rebuild pictures and realized that this was the one hole that also had to be helicoil-ed
Does this stud hole go in to the water jacket and as such just needs to be re-sealed, or do I have a bigger problem?
I would talk to the machine shop and see if there is fix for this problem as I bet it is very common on old engines. It must be either a crack or a puncture into the cooling system.
Off hand I could only suggest maybe removing the Heli-Coil and filling the edges with high temp steel epoxy putty... and while soft reinserting the Heli-Coil and retapping after it sets without going through to the water jacket.
Heli-coiled manifold studs that purtrude into water passageways can be troublesome to seal. All too often they flex and rotate slightly when being installed and removed leading to leaks. The is a place that fares much better with nutserts which are easier to seal.