Great! Thanks for the recipe for the citric acid mixture. Not having any advise earlier I ran a little shout through it. As mentioned, the car overheated (got up to 120°, just below the redline but just momentarily. The recovery tank was belching and boiling over vigorously. I flushed it out after it cooled some. Today it ran a lot longer before it got too hot. I ran through a few gallons of acid, probably close to the mixture just suggested. Once again though, after a short while it heaved up out of the recovery tank. The oil goo just sticks to everything though. Some comes out but there's a blobby film over everything.
I think the over heating is because the radiator is all gunked up. I may have to put in the new one just to be able to flush out the rest of the system. There's just doesn't seem to be enough circulation now.

On the M103 there are a couple threaded plugs at the front of the head along side the valve cover on the intake side. I believe either one of these is used to de-gas and check the water level in the block. There's also a bleed on top of the thermostat housing.