[Clint]

There is no reason not to switch right away. Modern engines are built with much better tolerances than days of old, and many engines come with synthetic from the factory. I have not seen anything other than anecdotal evidence, ancient advice, and recommendations for rebuilt engines that suggests otherwise.

Vic

I'd think those with a synthetic factory fill may have an even tighter tolerance to do so.
Maybe call an engine builder and get a current day expert opinion on the subject?

Clint

 

[Clint]

Interesting that you pointed that out, when I picked up my 2014 Sentra SR new the salesman said it must use synthetic and it wasn't a suggestion it is mandatory, it uses 0w-20 while all of my Nissan have always used 5w-30.

Clint