A couple months back I bought a 1984 244 GL. It's got 135,000 miles on it now. Up until tonight everything seemed to work great, except for a leak in the fuel system near the back of the car, and a couple minor electrical issues with the dashboard lights.

So last night I was driving down the freeway and the engine began losing power. Not a lot, but I needed too much throttle to maintain speed. My dashboard lights are out, and it was dark, so I couldn't see the temp gauge, but I pulled off the freeway immediately and turned the car off. At low RPMS, sub 12-1300, there was a very loud clattering.

My first thought was that I'd thrown a rod, but when I got the hood open and looked, there was no sign of any physical damage anywhere. The steam from the coolant was SCREAMING out of the expansion tank, which was shaking and shuddering from the boiling. There was no sign of any other fluid leaks.

Pulled the dipstick, oil was fine. No hint of coolant. Pulled the oil fill cap, and everything smelled fine in there, if a bit hot. Coolant smelled fine as well.

I towed the car home, and consulted with my neighbor, who manages an AutoZone. He said he thought it sounded like the thermostat was just bad. I picked up a new thermostat today, pulled the housing, and sure enough - the thermostat was pretty well shot to hell. The arch on the upper side of it was broken, and the spindle through the center was canted about 15-20 degrees off center. I pulled the thermostat out and that's when I got the BIG surprise.

Looking down into the hemispherical area where the thermostat sits in the head, you can clearly see the coolant tube leading down into the head. BUT there's a big chunk of the hemisphere missing as well. Looking at it as if it's a clock, from about 10:30 to 4:30 or so is missing. The inner and outer edges both look clean and smooth, but the left and right edges are a little jagged.

So the question is this: is that supposed to be there, or did I lose a chunk of the metal of that seat? I haven't re-filled with water yet, and I haven't tried a test drve either. Sitting overnight, there were no (unexpected) leaks underneath the car, and I can find no readily apparent reason aside from the t-stat for the overheating.

This is the first brick that I've owned. I'm pretty mechanically savvy, and I've got a good grounding in Saab mechanical stuff, but my Volvo experience is somewhat limited. Any suggestions or help would be greatly appreciated.