[FNA]

"even if you use syn oil you still have to change it every 3k or when it gets dirty looking, I confirmed this after my pulling my friends nissan apart that he always used mobil1 in and 7500 mile oil change intervals."

cammy1, it is absolutely wrong to change syn oils at 3,000. really don't need to change regular motor oil at 3k for the sake of the oil, but using syn oil it is a huge waste of money.

I would venture to guess that your friend's Nissan engine condition had more to do with driving habits or some other factor than with changing syn oil at recommended intervals.

i am surprised that you as a mechanic would say "suspect a bearing going or gone bad in the bottom end...Id rebuild the engine when it gets loud enough." What? When it gets loud enough? Yeah, just continue damaging the engine more and more until you can't stand it anymore. Gotta say, no wonder you have rebuilt many engines.