Really, becuase i've done several somewhat difficult repairs on my X and i have no desire to try the vavle adjustment, reading the step by step you have to mess with the cam shafts and all sorts of "internal engine stuff".Like all engines, lifespan can be extended if it's maintained well not abused. I'm at ~158000 today, original owner and the first actual repair I had to do was replace the oil pressure sensor at 141,000/11 years after buying it. That's a pretty good track record for any vehicle. I used Mobile 1 full synthetic from the first oil change onward and had to replace the timing chain guides at around 145k so that doesn't have a big impact in my view on 'preventing' the guides from wearing. That said, the guides are plastic for a reason and are a wear item that will eventually need replacement. Lastly, I think that anyone who paid to have their valve clearances adjusted probably also paid for a gallon of full synthetic blinker fluid if you know what I mean. :laugh:
Im thinking about just dropping it off at nissan for both the timing chains and the vavle adjustment all at once.
I like working on my own vehicle but there are somethings that i think are alittle too much for a weekend garage tinkerer.