I think a 1cm movement in the actuator rod is approximately the full range necessary to take the variable nozzle from closed to open and if you are getting this range of movement does it not indicate that the vacuum system and actuator is ok ? The variable nozzle mechanism is not likely to be jammed but of course as said already movement in the actuator rod will not show up the vanes sticking maybe when the engine is very hot but when you take the whole thing apart its a fairly loose fitting type of setup and looks fairly reliable to me . If the internal actuator ring breaks ( it moves the bones which are attached to the vanes ) this could jam the whole thing solid but then the actuator rod would hardly be able to move at all . You could also have a situation where the actuator ring is broken but is still able to move and open and close the vanes but obviously then not in the correct way , the only way to be sure about this is taking the turbo apart , I think I would look elsewhere for the problem before doing this . The variable nozzle turbos I have taken apart are from high mileage diesels and apart from a coating of very fine soot around the bones ( no soot on the vanes ) they were ok showing no sign of wear even though the rest of the turbo was goosed .
|