What about turning the engine over by hand? Did any coolant come out of the 13/64 hole? With the gaping hole being in the intake and not coolant and the new info you have provided, I have new ideas as to plugging it up. I'll draw and post a diagram later, which will be better than words.

Since you breached an intake passage, that coolant is probably in the piston.

I didn't turn the engine by hand. Not even sure how to do that.
The gaping hole is higher than the small hole where coolant was coming out of. So the only coolant that would have made it into the intake passage would have been a small amount on the initial breach when I drilled the small hole too deep.

Funola. Interested in seeing this drawing. Thanks for doing that. Take your time.

1/2" drive socket on the crankshaft pulley nut (not sure size on 606) and a ratchet. If you can't turn the engine a few revolutions, coolant has gotten into the other cylinders via the intake runner and is hydro locked. You'll have to remove the other glow plugs or injectors to blow it out.

If I remember correctly, this is impossible on an E300. On a 123/126 with a 616/617, it works great (27mm socket), and is the best way.

Is there an alternative? How do you set TDC doing IP timing? Power steering nut?

There is no room to get in there as is. I need to start disassembling a lot in the front to get a hold of that pulley. How necessary is this step? If I can get to it, clockwise or CCW?

I was ready to buy all the plugs, bolts, Loctite, JB Weld, etc that I need and button this thing up already.

I haven't removed any injectors. Was hoping I wouldn't have to, but none of the other Glow Plugs are in yet. Once I broke off the one, I never bothered installing the new ones yet. If there's a way to just 'blow it out' why don't I just do that in case there is coolant in the pistons as opposed to turning the engine by hand? Is that a possibility?

I am sure there is a way, but it is not with the power steering nut either (there is none).

The idea of turning the engine over a few turns, slowly, by hand, is to push out the coolant which may be in the cylinders, without possibly harming the engine. If you use the starter motor to do the initial push out of the coolant, it may hydro lock and cause some damage. If the other 5 glow plugs are out currently, you do not need to remove the injectors. The coolant will be pushed out of the 5 empty glow plug holes and the 13/64 hole. After you turned the engine over a few turns by hand, most of the coolant will be out and it cannot hydro lock anymore and you can then spin it with the starter motor and blow the rest of the coolant out of the glow plug holes.

At 5:00 min mark in this video https://www.youtube.com/watch?v=2DHD6UoALto Dieselmeken turns the 606 engine with a socket. His engine is out of the car though. Maybe others will have alternative ideas.

Edit: With gloves on, try to grab the power steering pulley and another pulley and see if you can turn the engine. With glow plugs out and not fighting compression, it may be possible.

I'd remove the injector for the cylinder associated with the breached intake runner, and then crank it over with the starter. Need a new heat shield under the injector, or "reset" the old heat shield so that it seals again. Someone has posted how to to do that before, wish I'd bookmarked that thread.

You can try this - http://www.peachparts.com/shopforum/2831001-post4.html

You're right, the injector for the cylinder associated with the breached intake runner (and breached coolant jacket) must come out. The injector hole is the only outlet since the glow plug remnant is still in the head.

Every time I think I am nearing the time to plug this thing up you guys throw me another curve ball with more test procedures to be done. Please bare with me as I am trying to understand this.

But if the injector hole is the only outlet then how are you proposing the possibility that coolant got in the cylinder in the first place? (which we don't even know has happened)

And if the answer is: via the large gaping hole in the intake runner, then wouldn't that serve as an "outlet"? (what goes in, must come out?)

As far as hand cranking the engine. I tried last night. It's just too tight to get a socket in there without removing the fan. And even then, I am not sure there is room. I attempted to grab onto whatever pulleys I could and try to turn one. I grabbed the belt and tried to get it turning that way. It's just not happening. Impossible to get a good grip on anything with the limited amount of room.

The coolant went in via the intake valve(s) from the intake runner breach. Whatever cylinders with open intake valves could have taken in water. My apologies, I was wrong when I said you could push out the water via the 13/64 hole which hit a coolant passage, and is not connected to combustion chamber.

Edit: Picture this:

After you drilled through and into a coolant jacket with the 13/64 drill, coolant flows out and rise up and drains into the large gaping intake runner breach. Because the expansion tank cap was on, it took days for the coolant in the expansion tank and head (up to the level of the breached coolant jacket) to completely drain into the intake runner.

No apologies needed. I am just trying to understand the anatomy of the insides of a cylinder head. As you can see I am not aware on what passages interacts with what.