while going up a mountain, my 1981 300SD turbo started to overheat. I drove it a bit longer than I should but stopped it before to long, added water from a campground and seemed to be ok but after 20 or so miles started to overheat again. I stopped and let it cool down, added water and went around eight or so miles, overheated again, same procedure, did this several times until I got it home. It did not seem to be running very well by this time. Now it will not start. Battery is ok..I tried WD40, no luck there, God help me I ever tried a little starting fluid(I am sure this is a no-no). I am told it could have lost the temper on the rings(it has about 250k). also other problems. I would like some opinions on best course of action before I do an engine change(will need advise here as well but first things first) Thanks....Ken Jensen

 

KV, I am not really sure what to say. I am sure that you know that Mercedes Benz coolant systems are just barely adequate even on new cars, so one of the most important things, if not the most important things to watch on your Benz, ESPECIALLY the DIESEL cars they produces is coolant temperature.

You say that you saw it overheating, how high did the coolant temperature get.

Now, it is hard to say what could be wrong. WHen your engine overheats a whole host of things can happen, you can blow a head gasket or seize the bearings.

Can anyone else chime in here?

 

Does the coolant have oil in it? Or the oil have coolant? If it does you know the answer.
You need to pull the injectors or glow plugs andcheck for water if the engine will turn over.

 

When these engines overheat the liners warp causing the engine to loose compression. It was probably warped just before you shut it off and it was running poorly. Once it has cooled you dont have enough compression to start.
I would start with a compression test.
You can tow these cars to start them. I would do that before I would use starting fluid. If you crank them too long you wash the cylinders with diesel
and you can loose compression for that reason.