Wow.precombustion chamber come loose in the head
Be wary of manual maintenance schedules. This is a classic one. Tappet clearances shouldn't need adjusting every 20k. However if people can't do it themselves they will book into Mr Nissan (he hopes) every 20k to get it done. If you can do it yourself go for it and tweak them every 20k but really it takes longer than that generally. After 70k on mine after purchace (114k) I checked. They needed no adjustment. Well not really. It was hardly worth the effort. After another 70k they are getting a little bit noisier on a cold morning so it is probably time for a look.From the Service Manual.
Mate glad you saw as I did. If you can do it yourself, like tinkering and have in your own maintenance routine it will only do good. I just feel sorry for those who pay someone to do everything just because the manual says. Needed or not.Get what you mean, Mine have been out by 3 thou.+ over a 12 month period, but most times not to bad, I just do it with my pre-summer coolant service every year, 15 minute job nearly lol. theres allways one or two that need adjustment.
it was only my suggestion after I chased a ticking sound for ages in my old one..went away when cracking injector so replaced injectors, sound got louder, got tappets all redone to eliminate any wear and tear (they round over underneath so you cant get a proper reading with a feeler gauge), noise still there... pulled head off and precombustion chamber was loose in number 4...it is actually pretty common in these as they are purely a press fit and if you do a lot of towing and the head gets heat into it the chamber heats and cools different to the head and simply comes loose...they also crack quite regularly..Wow.
Plausible, but let's not worry him too much.
This possibility is way down the troubleshooting path with this problem I would have thought. We don't need to rip the head off at this stage. Maybe in the future but not yet.