I know this question is a doosie but is it possible to move everything above the valve covers to see which lifter is the bad one? cuz I took mine all apart used the feeler gauge on every lifter intake and exhaust starting from TDC on the first pistion and following the fire order! Yes I have tapping.Full synthetic oil.everything has been replaced above the lifters gaskets,o-rings and relearning procedures have been done.with the exception of the timing chain to which i dont want to mess with.Theres almost 1000 pages on these forums I don't have time for lol.can anyone give a list of potential causes I can figure the fix later.thx in advance.

 

So I tried it took off the air plenum and the wiring harness and then the valve cover,then plugged everything back in...and didn't see anything out of the norm,but if it was a lifter tick what should've i been looking for?

 

Nissan recommends mineral based oil due to valve clearances. Using synthetic oil can cause ticks.

 

How come many on here recommend Synthetic?

This isn't the only thread I've seen.... but it is a few years old
https://g35driver.com/forums/engine-...uld-i-use.html

I'm putting oil back in today, what's best? Would 10w-40 be better than 10w-30 in FL where it never gets too cold.