im swapping, or attempting to swap an h23 manifold onto my f23 block. i want a bigger manifold since the tiny f22 one i have on is just sapping power from the turbo. anyway, there is a coolant passage on the block that does not line up with the h23 manifold. this leads me t my main question, what the heck does that coolant line do? where is the coolant going and can i block it off? all the writeups and tech articles ive read all indicate that its safe to block the passage on the manifold side, and that it should not be an issue.

can anyone tell me what the coolant passage may be for because i havent managed to find out yet and i dont want to block it without knowing what it is.

to give a little more info on it, if you are looking at the manifold looking into the runners, it would be the nickel sized hole on the left in the bottom corner.

 

nobody knows the answer huh?

 

on the other side of the H23 manifold you should find 3 hose connection. One goes to the FITV, one goes to the IACV and one goes to the throttle body. Thats where the coolant coming through that passage is going. It should like this...

 

ok, so, i can in theory block the passage on either the manifold or on the head, and not worry about anything not receiving coolant? as far as i know, the passage can be left open or closed depending on if you can rig it up to flow etc.

so, does this mean that with the correct thermostat housing from the h23, the whole thing will run on the f23 motor? as far as i can see, it shoudl work, i just got sent a non h23 thermostat so i have no clue as to whether the new one will fit.

 

If you aren't using the FITV or the IACV then I don't see why not.

It should work on the F23 like it works on the F22Bx. You will need the correct thermo housing though, I believe the F22Ax thermo housing would be the same as the H23.