I have read the million threads on this subject and still have not reached a conclusion, Thought it may be easier to throw a poll question out there. I'm running Rotella t6 synthetic and have heard your ok up to 10 000 kilometres. Who's doing this?
why not send your oil off for analysis at all of those mileage intervals, then you will know WITHOUT A DOUBT, when your oil needs to be changed..
your power levels will also be a big factor..
my 1.6TD will wear a change of oil out, in around 3500 miles.. like worn clear out, sheens off metal like water on glass..
and thats because the engine is soo SOOTY that the oil just cant handle it long term..