2.5 Water leak on exhaust manifold #1 front threaded stud

[airspeed]

My rebuillt 2.5 long block has developed a water leak on the front threaded stud of the # 1 exhaust port? Is this threaded into a water jacket? What would be a good way to seal the stud?

[Cheech]

I'm not sure if that stud is threaded into the water jacket, but I know for a fact that the front head bolt on that side of the engine threads into the water jacket. The service manual calls for some pipe dope or something similar to be applied before installation. Any chance that its coming out of this head bolt??

[airspeed]

I pulled the stud out and sure enough it threads through into the water jacket. I put some "Honda Bond HT" on the stud and threaded it back in and appears to be working OK, no leak, time will tell...

 

I have been looking at this silicone called Honda Bond HT, this is some impressive stuff. A very high temp silicone 600+ that resists oil. I did a small unqualified design of experiments and compaired it to the high temp Permatex Ultra black, it may be a better sealant. I will have to try it on a few differnt applications to make a better judgment. The only trouble with the Honda Bond HT is the price $$, what is a good seal worth?

[aemsee]

that does not normally go all the way in to a water jacket. Someone must have drilled out a broken stud and gone too far. Did you buy this as a reman engine? If so I would complain to the place you got it from. They owe you a new head.

[airspeed]

It looks like that leak is taken care of, I will keep an eye on it. Now I have a new leak, the 6" water pipe that angles up out of the maniflod. Looks like I will have to remove the throttle body assembly to get that one out. This is just one thing after another. I wanted a little project to work on, now I have it...