I just recently purchased a brand new water outlet cover for my B16a. The water outlet cover is the part where you bleed your coolant system. It is item# 6 on the honda diagram. And it did not come with any threads tapped on the two holes I posted below. I asked the Honda dealer about it and they said that this is how it comes from the factory. So, my question is does anybody know the exact thread measurements for the two tapped holes. Any info would be greatly appreciated.

 

Those holes aren't tapped. The bolts go through the hole and thread into the head. Use a bead of HondaBond on the mating surface and tighten it down. Wipe off the excess HondaBond and you are golden.

 

The two holes that I marked are suppose to be tapped. One hole is for a nipple fitting. And the other hole is for the bleeder screw.

 

Sorry I couldn't see the image, it was blocked by my work computer. Do you have a bleeder screw to put in there after you tap it? If you do, use a thread pitch gauge to see what it is.