'95 Jeep Grand Cherokee: How bad is this going to be?

Hi:

Had a breakdown last night, I'm pretty worried about what might have
happened, any advice or enlightenment will be greatly appreciated. Here
is the sequence of events:

- left work at about 7:00pm in very cold weather (-20C).

- as I was entering the highway, my Jeep hesitated a bit like it was
going to stall, but then ran fine.

- within a few moments, the thermostat went through the roof, so I
pulled off the highway at the next exit. The coolant was very low
(nothing in the resevoir), so I bought a jug of coolant, topped it up
(about 2 litres to bring it to the fill line).

- the only other sign of trouble to my untrained eyes was that the rad
was still cold, and the heater was generating zero heat. No apparent
leaks, steam, smell, etc.

- tried it out again to see if the temp would come back down.

- Still bad, so I pulled off the road. While trying to get back to the
gas station, there were dieseling sounds and the engine ran very rough.
I couldn't even get to the station before the engine stalled. The
engine *would* turn, although it was labouring. I thought better of
trying to force it.

- at this point there was steam in the engine compartment, and not to
steer you in any particular direction, but it seemed to me to be coming
directly out of the perimeter of the cylinder head.

- had the vehicle towed to the only place open at almost 8:00pm: Crappy
Tire. The vehicle is there now and I'm waiting to hear.

My opinion is the head gasket is blown, and dumped coolant in the
combustion chamber(s).

So, my questions are:

- Why? Does the fact that the rad stayed cool throughout mean something
froze and caused this situation? Or is the root cause the (possible)
blown gasket, thus the coolant followed the path of least resistance,
i.e., not to the rad?


- What now? Given the high temp, possible contamination and definite
laboured engine turnover, is something totally pooched at this point?

- What is the general procedure for fixing this? Is it possible there
is no major damage? Can the (possibly blown) gasket be replaced, the
engine flushed, the oil and coolant replaced and hope for the best?

Thanks again.