My car overheated and the radiator and thermostat broke. I replaced the radiator, thermostat, and hoses in my car:

92 Civic EX 4dr AT, 16 valve engine (don't know where it says 1.5/1.6 L)

After completion, car was running normally (not driven though), then I attempted to do a check for any remaining air in the system by loosening the bolt with the little hole in it on the engine block where the top radiator hose connects to.

The bolt, along with the cement engine block area that it was encased in, broke off. I can clearly see the water run through the hole.

Do I need a new engine? What other options do I have? I am a novice, some help would be greatly appreciated... though I think I do need a new engine.