The difficult thing about this topic is all the talk about it on the net and its difficult to know what to believe and its hard not to get sucked into all the negativity. What I have seen is that most of the negative feedback from people is in regard to the patrol zd30. From my experience, I have not read about any Navaras with the same problem, ie blown pistons but I have read about a few navaras with blown turbos (my injection mechanic has also blown a turbo). But what you hardly ever hear about is how the vehicle is treated. Mine was serviced at the intervals recomended by the dealer which I think is incorrect, the service manual recomends oil changes every 5000, which I will be doing from now on instead of putting my faith into dealer recomendations. There are a heap of precautions you can take to reduce the risk of failure. This is what I will be doing:
1)5000km interval oil changes (for obvious reasons)
2)Intercooler (to catch the bits of turbo)
3)EGR Mod (to stop putting dirty gases into the engine)
4)Catch can (stop the oil and carbon build up going in the inlet)
5)Exhaust system (breathe easier, allows heat to get away)
6)EGT and Boost guage (to monitor any abnormalities)
But without a crystal ball, how do we know that our engines will last the appropriate time before a rebuild for a diesel, I would say at least 400,000km's, I am not sure any Navaras would have reached this ammount of k's yet. I guess we can't tell as they are not old enough. In 10 years time will people be saying, 'gee, i wish they still made navara ZD30's, they were bullet proof'. Who really knows? It is a bit of a gamble when anything hasn't been proven over a significant period of time. It's just a shame they are so damn expensive to repair.