So you have about 112K miles on your 2018. It it making sloppy chain noises? If not, you should be good to go. Main thing is, how often have you done your engine oil changes. You almost have to do them twice as often as Nissan recommends if you want maximum engine longevity on the VQ35DD. I'm at 100K miles on our 2019 that was an ex-rental that basically had one oil change at 12K miles, then another just before I bought in 2019 with 25K miles on it. I've been doing them every ~3500miles since, with 5w30, because synthetic 5w30 makes me feel better than thinner 0w20. I have zero signs of sludge in my oil filter media when I cut my used filters open and she looks clean down the oil filler hole yet.
When cold it makes a pretty loud ticking noise, almost like a diesel engine. Difficult to tell where the noise is coming from, other than that it's in the engine bay and it quiets down when RPM is lowered.
It's always been kinda loud, and I've equated this to the injectors rather than timing chain-- but as it gets colder outside it does seem to be getting louder. I hate paying shops to work on my vehicles,
I do my changes
at least every 7500KM (~4600 Miles). I am now going to be shortening the interval to 5000KM (~3100 Miles), and I've always used the recommended fully synthetic oil. I don't remember off the top of my head if I'm using 0w20 or 5w30-- I believe I stuck with 0w20 as I live in a colder climate. In Canada, Nissan recommends either.
I do like your idea of cutting open every filter, though, I'm going to start doing that.
