I'm grappling with these same questions because I'm now at about 4K kms.
Also, does anyone know what's in the EX35 crankcase as delivered? a. regular dino oil b. synthetic c. special blend used for engine break-in d. other??
There have been a ton of discussions in the G forum about the advantages and disadvantages of synthetic vs. dino oil. I'd suggest someone do a search and post the links for the full story. (there are several threads)
Basically, many people favor the synthetic even though it costs more. However, there might be a problem leaving it in the engine as long as they claim it can be left in there. They also report a slight gain in MPG. I'd suggest checking a few threads in the G forum for much more info.
My two cents on synthetic oil. I have used synthetic in my last three vehicles. (2 Hondas and a BMW) The Hondas all went well over 150,000 miles and were still running strong when I got rid of them. The BMW was at 120,000 when I traded for the EX and ran like new. I intend to start using Synthetic in my EX at the 7500 mile change and every 7500 there after. Infiniti warranty accepts this as a valid service schedule. This is what I did in my BMW and the oil was still clean at every change. BMW even recommends 15,000 as their schedule with full synthetic. I personally would not go the 15,000 mile or more changes advertised by some of these synthetic oils, not so much because the oil will not last, but because I dont think the filters are capable of performing for that long. Since the EX comes with regular oil from the factory, I just had the dealer perform the 1st change (3750 miles) with standard again, then it will be Full Synthetic at every 7500 mile scheduled maintenance after that. Yes synthetic does cost more, (my dealer charges $40.00 additional), but you are only changing the oil half as much, and using a superior lubricant. Some my disagree, but from my personal experience it works for me.
