What kind of damage can occur by overheating until the motor stalls
 

on a 1977 240D

someone i know was driving around the city, circling blocks looking for a parking spot. apparently during this a radiator hose blew and/or coolant otherwise drained out. the temp gauge on their cluster is non-op so they didnt notice the car overheating at first. apparently they did notice it when lots of coolant/vapor came pouring out from under the hood. at this point the motor died. they were able to get it restarted briefly to pull over for safety until they had it towed here.

what kind of damage could we be looking at here? we started and ran the car again (very briefly, for less than a minute) to move it to the other side of the street. i didnt notice any hard starting/weird noises. should we be looking at testing the system for head gasket failure?

The Cylinder Head gets the hottest so it could get warped or cracked and/or causeing a Head Gasket issue.
Turn the Engine over at least 2 complete revolutions by Hand to see if anything is hanging up.

If it lost Oil Pressure due to overheated Oil that could effect the Timing Chain Tensioner function of being able to tension the Chain; as the 240ds don't have that Ratchet to keep the Tensioner Piston being pushed back. TheTensioner is pushed out by the Spring and the Oil Pressure.

You could simply fill it back up with Coolant and see if it starts and liste to the Engine.

A comprssion test could show a Head Gasket issue.
Pressurizing the Cylinders one at a time with compressed Air could show if there is a leak into the Coolant.

If it got hot enough long Enough the Cylinder walls can get scored up.

You can drain out the Oil and look in that for metal fragments and in the Bottom of the Oil Pan if your Engine has a removable lower pan. Depending on what the fragements are made of will tell if there is major bearing and journal damage.

There is a very good chance it is ok. I'd fill it and change the thermostat and see what happens.

Whether it matter or not in the compression config, on an ignition engine, ( Like my Chevelle's 427 - first hand), over heating can damage ( un tension) the oil rings; and possibly the compression rings, as occured on a spark engine. ( actually heard them 'tinkling' as it cooled) If you get as far as pulling GP's or injectors, a compression test, and leak down, would tell all.

and I pulled the oil filter apart when it happened to the 427, to see if any metal was present.

Happened a second time, worse in elasped time, but we shut if off frequnetly, and the first test was a compression test, as coolant pressures went thru the roof when the pump failed.

We'll say a "prayer" for it!:cool:

As a general rule if the engine did not blow all the coolant out you have a chance that no damage transpired of any signifigance. Driving around with no coolant for a time and no temperature gauge to observe may or may not be another issue.