I sure could use some help. Quick story short:
We were ready to fire up the 540 cubic inch Hemi Saturday. I was fitting fuel lines while my son was putting coolant in the radiator. As he was filling, he noticed coolant coming out of the oil filter. Tore down the entire engine only to find that coolant was coming in from the oil return hole on the passenger side near the front of the block. Turns out that there is a breach between the oil return hole and the coolant cavity. Has anyone ever had this problem? How do I fix it? The block is a cast iron Hemi Mega Block. It looks like a casting defect and there is no way I can get to it. Any suggestions would be greatly appreciated.

I would tube it like you do with push rod/port interference. Get a tube the size of the drain, and epoxy it in place.

That is exactly what I was thinking about doing. Do you have a suggestion on what type of epoxy to use? I am worried about expansion and contraction over time. I was thinking JB Weld?

The breach is about 2.5 inches up from the bottom of the block (viewed from the crank side). I was also thinking about tapping past the breach then use a threaded rod with a hole in the center and seal it that way.

Sounds sort of familiar. Sent someone a email.

Just curious, what is you casting date?

Not sure off hand. I'll check tomorrow. I believe it is early to mid 2000's?

You might have to drill or ream the hole to a certain size and then drive the sleeve in.

I will have a tube made at work that will be a slight interference fit. My plan is to freeze the tube then quickly drive it into the bore. I would like to have some added insurance of some type of epoxy. Does anyone have any suggestions?

Marine Tex It is has been used in the boating industry for years for gas tanks to hulls of all types IHTHs That or Loktite Green sleeve retainer