Recently I spent a good couple of hours ringing several nissan dealerships within the country (I spoke only to service and parts, should have seen my phone bill haha) I also spoke with a few independant mechanics who have been working on diesel engines since the old school 90's.. they have had to learn about them all over again (the ones who know the differences are the best I think) Yes yd25 are complicated (more than they should be perhaps) The consequence of Nissan's progress is the YD25 are a delicate engine. The correct and PROPER maintanance needs to be carried out EVERYTIME and your yd25 will purr like a kitten. For example, even the smallest neglection or overlook could set off a reaction which ends up exhausting your wallet, like driving without giving your car the chance to warm up. Little things like that contribute to rapid wear and tear, and seeing as the sprockets which the timing chain rotates on is so weak, guess what will be affected by rapid wear and tear? Yes it's that simple.. just change the sprocket wheel when your chain sounds like it's rubbing on metal, it's that easy.. and cheaper
So when something goes wrong.. everyone points the finger at nissan and they don't want a bar of it. Of course they don't want a bar of it, in their eye's you have mistreated the engine so why should they honour their warranty? Nissan built an awesome ute in my opinion.. too many yahoos out there find it easier to blame someone else other than themselves for their lack of common sense. As for duplex timing chain.. I have no solid proof, but a reliable D40 owner who happens to work on exhausts has said the same thing about duplex timing chains causing problems.
One comment that was said to me a few times was, 'if this duplex timing chain was soo effective, then why didn't nissan add another and then they could justify putting 3-4 grand on the sale price?'
Truth is mate, yd25.com.au is ripping people off on a massive scale. STAY RIGHT AWAY FROM THOSE JERKS