Just had my 2004 zd30 do a flywheel, horrible noise on startup, and then rough idle, 4terrain clutch and flywheel installed. But they couldnt diagnose it at the start and pulled all the timing covers and related stuff thinking it was a timing problem, well it was right on xmas lead up!! Anyhow had a new water pump belt tensioner and hoses thermostat and that replaced at same time, #$$* expensive, $192 for a belt tensioner,$531 for a water pump, anyway she runs like a kitten, and they changed the oil and filter[genuine] and when i got her home i changed the airfilter[genuine], and the fuel filter[genuine] and that has made a difference, dont use non genuine fuel filters, they are smaller and not as fine a micron, mine starts with out a hiccup now, before it used to take a couple extra turns on occasions. Im also a Delo 400 caltex man, but they[nissan] have put 15/40 magnatec in, and it seems to run quite and smooth and starts with little or no rattle, so i guess its ok, anyone else run this oil, it seems to be upto spec for nissan as they told me thats what they reccomend. Anyone else had similar experience, let us know.