I've never had this leak before on any car in my shop, and never questioned what it was for. It's bleeding oil right below the valve cover in a little port that looks like it has a ball in it, between the cyl 2 & 3 intake runners. I tried searching around and got nowhere on this.
See attachment

 

I just read through the entire cylinder head section in the FSM, and there's absolutely no mention of it. Is this what you're looking at?



And it isn't related to air assist, either. That hole is lined up with where the injectors would sit, but the air assist holes sit higher than that. Is the head from a 96-98, or 99-00 car? A 99-00 stock manifold would cover that hole and seal it off...Beyond that, I'm just spitballing.

 

I don't believe I've seen that ball before at all.

What year is your head @OP?

 

https://honda-tech.com/honda-civic-d...-head-1080958/

i believe they discuss that ball bearing in this.

 

Huh, well there ya go, it's from casting. Safe bet you can just drop a tack weld in the hole and call it a day.

 

This from that thread would indicate the bearing is to seal it up and yours is leaking so NARC appears to be right about tacking it closed.

It was stated that it's from the 99-00 Y8 heads. That's when the casting changed.

 

Is it dripping out? If so I'd clean it up and hondabond that ****.

 

Just close it up and call it a day.
Its probably happening because you have a different manifold which doesn't close the hole up already.

 

yeah I just changed the mani and noticed it, that is the hole that's dripping. The head is 96. I can't think of any legitimate function for it either, I assume it was a last minute manufacturing fix for oil porting, maybe running it back through the weld assembly would have cost more than plugging it with a ball. I'm just gonna seal it, the mani blocked it off anyway. thanks for the ideas fellas

 

Just to clarify, nothing head wise changed from 96 to 00. These all share the same head and part number. The FIA (air assist) only changed from an intake manifold and intake manifold gasket perspective.

 

Well, I plugged it up with some Hondabond, and after a few days ripping on it at 18psi with the comp cam it hasn't fallen apart yet. definitely isn't leaking.

 

Good follow up

How long did you let the Hondabond set up before driving?

 

WTG!

I just recently had a 2000 Y8 installed in my car. I don't leak a drop of oil. I suppose I have whatever manifold that is to thank for this.

Good stuff, OP!

 

I let it set overnight. I've been driving it pretty hard, as usual. No leaks from it. Yeah, I think most manifolds cover the port.
PS don't use those thick teflon-type heat resistant intake gaskets on a turbo engine.
I had boost leak into my coolant system through the gasket :-/