Yeah, Nissan gets a bad rap, but the VQ40 is a killer engine as is the vk56. The originals really only had 1 issue, and that was the chains eating up the guides. By like ~2008, they had that fixed. Pretty much issues free otherwise. Mine's at 215k and other than replacing the timing components...
Newest UOA. 5k miles, 3 months, 65 miles a day of interstate commute. Did recently change timing chains and guide so thats probably the silicon spike, maybe also some iron?
Previously, I ran HPL Premium Plus for 2 x 10k oil change intervals and saw massive spikes in lead (See link to oil UOA)...
It seems to run fine for the most part. A few times on startup it has shook a bit almost like it wanted to stall, but corrected itself after just a second or 2.
It's makes some tapping noise at startup when below like 40°, made it before I did the chain replacement so it isn't new. I've been...
Guides were worn through, secondary chains were riding on the metal tensioner pin that applies pressure the plastic guide (which had worn away). I replaced the tensioners and guides. No slapping on the timing cover afaik.
So. See thread here for last update. Since then I've done some things.
https://bobistheoilguy.com/forums/threads/hpl-premium-plus-pcmo-5w-30-10k-mi-2007-nissan-xterra-204k-mi.400866/
After that uoa I did 2 x 1000 mile runs of super tech 15w-40 full synthetic to flush out the hpl and prepare...
Going to do at least 20k miles before I take the valve covers off and look. I don't think valv really states it'll clean varnish though, they claim it cleans rings iirc
Yes I cut and inspect all filters. I'll have to dig Up photos of the old ones but they weren't loaded with carbon or anything major and there was no metal in them. They honestly looked pretty good. I'll cut open the new one and take some pictures when I change it
Just want to point out. The filter was changed after the first 10k interval (actually changed when I put the oil in, then at 5k and again when the next run started). I just didn't change the filter or oil for this UOA yet as I was waiting to see results.
Gotcha. I'm aware of the chain tensioner issue. I haven't replaced mine, it's something I'm keeping an eye on but I don't have the tale tale noise or anything yet. When the time comes I'll probably do it myself, need to buy the parts eventually to have on hand.
Rad was replaced years ago with an updated one. No smod here. In fact, just changed transmission fluid at a 40k interval and it was still brand new cherry red. I'm quite active on the newx so I'm pretty up to date on the intricacies of the Xterra.
so we should be able to see this play out then. If I do a double flush and then a 5k interval of something other than hpl we should see lead drop a ton on the next uoa?