Frank, let's try to put this in perspective: of course synthetic will work well in your Nissan engine. Nissan's not really saying there'll be a problem (if they were, they'd spell it out), but rather since your engine warranty is contingent on specific OCIs, it's not really necessary to go to the
expense of a synthetic that's apt to be changed long before its capacity to protect has been exhausted. (for whatever reason, most OEMs continue NOT to recognize quality synthetic motor oils' ability to withstand extended drain intervals while protecting their engines...) That and the FACT that so-called "conventional" petroleum-derived motor oils are better than they've ever been, and the upcoming API "SM"/ILSAC "GF-4" oils month after next will be even better what with the anticipated increased use of Group II and Group III (a legitimate synthetic at the
chemical level - it's called
isomerization in chemistry texts, and, as applied to motor oil lube base stocks, goes well beyond "refining".) In the end it's up to you. There's nothing about Nissan metallurgy and engineering practices that would preclude or result in harm coming to your new engine from the use of synthetic motor oil. Just be aware, though, if you do decide to use a synthetic motor oil, and balance its expense with extended OCIs, you're playing Russian roulette with your engine warranty in case of the admittedly remote possibility you find it necessary to file a claim. (even Nissan misses the hoop occasionally...) Best of luck with your new wheels!
[ June 02, 2004, 11:07 PM: Message edited by: Ray H ]