Since acquiring my '84 300D Euro, I have done a fair amount of research on the nature and function of turbochargers. They are fascinating devices, and I wonder why ALL diesels are not turbocharged. My 300D has an intercooled turbo, which, as many of you well know, cools the compressed air before it enters the intake manifold, thus increasing boost even more so than a non-cooled unit. I also understand that turbos are cooled by the existing oil circulation system, since they operate at a very high RPM. My question is this: should there be oil present in the compressed air lines going to, and coming out of the intercooler? I know it's there, because it leaks at the air line/turbo junction, and I cannot seem to tighten the hose clamp enough to contain it. As a result, I have to add oil to the engine, though it is not a prohibitive amount. I just want to know if the oil in the lines is normal, since this oil would obviously enter the intake, and hence the cylinders to be burned. What gives?

that just shows that your turbine bearings/seals are a little tired.
If you can stand the mess and as long as you keep oil in the engine you can run it like that for a LONG time. That is one of the beauties of the diesel - the engine does not care if the fuel is stored in the oil pan or the fuel tank. All diesel fuel is is oil that has some good Btu value.