TD engine missing core plug

["Ignacio A. Henao" <ihenao@sigma.eafit.edu.co>]

Can someone help me with how are the core plugs in a TD XPEG engine
installed? My car is missing the small one in the right side of the engine,
left of the water drainig tap. It appears as if the former owner, twenty
years ago, had replaced the plug with a thick coat of some sturdy adhesive,
that has now cracked and was leaking water. Now it is all gone and there are
two big gaping holes.

Ignacio