Coolant seeping.

[circlepilot]

My 225 build is about ready to be test run for the first time, (On my test stand). As I was adding the coolant to the radiator...too my surprise (and horror), coolant started to seep from under the intake/exhaust manifold at the cylinder head. What the hell is this all about? Has the head developed a crack? Did something go wrong at the machinist? I pulled the manifold assembly and found that the coolant was coming from several of the manifold studs. I had all of the studs replaced. No where (that I've been able to find in my manual) addresses the stud installation or removal. I removed one of the studs that had coolant seeping and by blowing air into the hole, surmised that the hole went into a water jacket. At this moment I'm drawing a blank as I don't remember if the studs needed to be sealed, or is something else horribly wrong?
Norm

 

[Charrlie_S]

Yes, all the studs need sealer. I use Locktite thread sealant. Not the white stuff.

 

[Syleng1]

Coolant also has a super ability to find every crack and leak available. As a welder I use it to sample test welds looking for defective welds. Over night you find rust stains if the weld is bad. Cheaper than x-ray for weeding out a bad welder.

Once your engine got hot those leaks would probably seal up. I also recommend sealer on those studs regardless. Quick question- you are using actual hardened automotive studs and not threaded rod right? The middle barrel helps seal once tightened into the threaded hole. Typically the threads do not go right to the edge there is a chamfer that protects the threads and seals against the barrel. I learned the hard way not to use locking pliers on those barrels to tighten them up. Double nuts on the end.
Syleng1

 

[Killer6]

My 225 build is about ready to be test run for the first time, (On my test stand). As I was adding the coolant to the radiator...too my surprise (and horror), coolant started to seep from under the intake/exhaust manifold at the cylinder head. What the hell is this all about? Has the head developed a crack? Did something go wrong at the machinist? I pulled the manifold assembly and found that the coolant was coming from several of the manifold studs. I had all of the studs replaced. No where (that I've been able to find in my manual) addresses the stud installation or removal. I removed one of the studs that had coolant seeping and by blowing air into the hole, surmised that the hole went into a water jacket. At this moment I'm drawing a blank as I don't remember if the studs needed to be sealed, or is something else horribly wrong?
Norm

Yeah, all the studs need the threads sealed up, great to see You're up to firing her up!!

 

[circlepilot]

All of the new studs are Dorman brand hardened studs. As by the comments, "the leakers" were not all seated completely. I Removed them all and cleaned the studs and holes with MEK. I reinstalled them with hardening permatex and a stud installation tool, torqued until the barrel of the stud was seated against the head. I'll try the coolant again this evening. I should of checked all of this before installing the manifolds (thought I did). I'm using aircraft brass exhaust nuts to install the manifolds. I'll report my success or not. I still find it hard to believe this is not addressed in my "1965 Plymouth service Technical Manual." Thanks for the replies.
Norm