Change the oil pronto, too -- it was the only thing cooling the engine, and believe me, you cooked it, probably even if it was synthetic.

The worst you could possibly have done would be to have scored the cylinder walls, but if it idled OK when you pulled off, that isn't a problem (it would have stopped!). Otherwise, watch your oil consumption and check for excess blowby suddenly appearing. When you get them really hot, the oil control rings de-temper and loose their "spring", so they no longer wipe the oil off the cylinder walls. Oil consumption goes way up, but compression stays pretty much OK.

Most likely you didn't do any damage. I'd have let it cool without adding cold antifreeze, though, for fear of cracking the head. Not usually a problem on the 617, though.

The reason I think you are fine is that my sister (actually my nephew driving) cooked the head on their Volvo 740 turbo a couple years ago -- the check engine light came on on the interstate and they drove to the next exit (argh.....). Upper radiator hose nipple was blown off, head was warped all to hell, the oil stank, but a new head and gasket (plus the plastic timing belt cover, it melted!) and they are still driving it.

You might want to watch the thermostat, too -- it's on the head on the Volvo and was shot, along with both temp gauge senors.

Peter

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1972 220D ?? miles
1988 300E 200,012
1987 300D Turbo killed 9/25/07, 275,000 miles
1985 Volvo 740 GLE Turobodiesel 218,000
1972 280 SE 4.5 165, 000 - It runs!