Quote:
Originally Posted by Mxfrank
You're overlooking another potential source for oil at the turbo, and the most likely based on your list of problems. The inlet of the turbo connects to the engine breather tube. There's not much flowing through the breather under normal circumstances. But with a hole in the pan and/or leaky engine gaskets, the breather becomes another source of air for the turbo. Drawing air through the crankcase also means drawing oil.
The turbo produces only 1 bar of pressure at full scream. Nominal oil pressure is 3 bar according to the gauge, but probably peaks at close to 5. So if you were dependent on hydrostatic pressure to oppose leaks, you would have quite a mess. The shafts and seals are designed to float on a film of oil, which is why they may seem to be a loose fit.
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Mxfrank, I like your thinking but I believe I did rule this out with my latest test.
After cleaning up the manifold and turbo and running the engine, I had the entire stock air system disconnected and/or blocked off.
I plugged the crank case ventilation tube and the turbo was sucking filter-less. In this scenario the only source of oil to the turbo would be the turbo's cooling oil. And yet, I still had visible oil on the inlet side and oil being ejected between the manifold and turbo.
(I also plugged the ARV vacuum connection.)
Would an W124 Garrett T3 bolt up to the W123? I read they used a slightly larger trim, I think. There's a really clean one on fleabay for a reasonable price. Depending on what needs replacing on my turbo it seems like it could be quite inexpensive or equivalent to picking up this lightly used turbo. The big differences here being I could sell my turbo to recoup some money and avoid the cleaning and rebuild process on my current turbo. I am *sure* it has some carbon build up in need of cleaning.