I have an oil leak in the area below the turbo charger in my '80 300SD. What is the most likely cause and how hard is it to fix?

P E H

The leak may be from the oil return tube or the turbo itself. Do you see a lot of smoke coming out of the tail pipe during acceleration? If you do, it may be because of the oil leaking from inside of the turbo into the engine.

There are metal 0-rings around the shaft acting as seals behind the turbine blade and the compressor blade. These seals cannot really stop oil leaking but more for keeping gas out. Oil goes into the bearing housing (center part of the turbocharger) to lube the sleeve bearings of the compressor (front part toward the radiator) and the turbine (rear part). The bearings are actually "floating" on oil. Oil rushes thru the bearings and goes back down to the oil pan. Oil leaking from the turbo bearing housing is due to the fact that oil floating thru the bearings is faster than oil draining back to the oil pan. Oil is overflowing inside the bearing housing. It usually starts leaking from the turbine side because the opening is lower then the compressor side. There are two reasons for that: 1. bearings worn out and/or 2. clogged oil return.

The oil return can be clogged because oil is drying inside the bearing housing when the turbo is very very hot at the same time you turn off the engine.

If that is true, it is time to rebuild the turbo. The above statements are the results of my research and they are not necessary correct.

David