Leak at side of engine

1996 Olds Achieva, 4cl, quad4,120,000 miles. Hi, I asked a question about this leak yesterday. Well, I was at a different location, on the leftside of the engine where the upper radiator hose, and heater hose connect to a plastic housing that bolts on to the engine, right below the oil sending unit.I had originally seen on the plastic the word, "thermostat" but couldnt read the rest(I need new contacts), Well, I got it off and it said, 'thermostat located at water pump". And this made me see some sense in your reply!Lol. Now, since I now found our there was no thermostat in it, I see whay it was leaking. The plastic housing seems to have some kind of ceramic-like material that has a groove for an o-ring, but it was broken badly, so the o-ring was loose.I am in the country doing this, so I freaked out. But I used the gasket for the thermostat to try and see if that would seal it, and am still checking it out. But what do I need, a totally new plastic housing. And a new 0-ring?It looks like the ceramic like material is bonded to the end of it where it goes in the engine(and seals with the o-ring), but I'm not sure>I dont even know how to describe to the parts people what I need, except to describe where the problem is. So, bottom line, all I need to do for now is get a good seal here, and see if the water leakis fixed. Thanks, oh, and thank you for the last reply Ben