I just got a replacement for my small and leaky Garrett T2, a nice KKK K24 turbo.. but while I was cleaning the outside I noticed that the exhaustturbine was coverd in goo-like black stuff.. I checked my old turbo and that was covered in crispy black deposit like the inside of an exhaustpipe.
Is the exhaustseal leaking on the K24 or could it be that the engine was burning oil?
And I measured that there is 0.45mm play on the intake side.. is that normal when there is no oil in the turbo?
another question would be do you ever have to clean turbos or do they just run OK covered in exhaust soot?
There isn't really a "seal" on the exhaust side of a turbo. There is a piston ring type seal on the shaft and positive pressure in the turbine housing prevents any significant leakage. Most likely the black goo is the result of prolonged storage with the turbo sitting on its end, or may have resulted from prolonged idling or oil burning from the engine that the turbo was previously installed on.
A turbocharger really doesn't need to be cleaned. Anything that can hang onto the turbine or compressor wheels at speeds exceeding 180000rpm and temperatures above 1400ºF is probably supposed to be there...
Chrissev: on every turbo I've seen the carbon deposits always form a nice layer on the exhaustwheel.. if it doesn't look that way you should clean it and check what's causing the problem.
and they play is ok when not under oilpressure?