My 2011 Nissan Navara D40 STX 550 V6 diesel engine has been regularly serviced and currently has 260,000 km on the clock. I've never used it to tow or done any off road driving. How many more km would you expect from this engine?
It's not possible to say with any certainty. Regularly serviced it could go for another 260,000 km, but if neglected it could breakdown tomorrow.
Relatively few of these engines were sold, so it won't have the same established patterns as a HiLux 3.0-litre for example.