Took our new G37 Sedan Journey in for its first oil change. Dealers are too far away for an oil change so took it to a local respected independent Japanese car shop. Car has just over 2,500 miles and wanted to get that first oil change for the breakin period. I asked for synthetic oil, but the service rep recommend regular (Castrol GTX 5/30) oil for the first 10,000 miles. He said the pistons will seat better in regular oil than in synthetic.

Since I didnt think it would matter that much for this change I agreed to have Castrol put in. But I've never heard this recommendation before, have any of you?

 

Rings are done seating in a couple hundred miles. Hogwash.

 

Dealer told me the same thing... put synthetic in at the 2nd oil change at the earliest. IMO, that's BS but I'm no expert. The only reason I gave the comment any credibility is that they can charge more for synthetic (and likely have higher margins) so they would probably be motivated to sell me synthetic. By telling me not to use synthetic until the 2nd oil change, I actually believe they "thought" they were giving me good advice. Whether or not it is true is something else.

Bottom line though is waiting a few more thousand miles to go synthetic won't hurt anything and saves you a few bucks.

 

never... People will say you should start out non synth. and slowly move up to synthetic. Which is pretty BS... I say go ahead and put the synthetic and keep it that way. But if you think about it going fully synthetic... do you really need it? Will you be driving the car hard, racing, etc?

 

OP The shop is right... Synthetic is actually thinner and does not hold engine particles as well as regular oil. The reasoning behind not switching until the first 10,000 is because since the engine is still new, metal particles that are coming off will be collected better in regular oil than in synthetic which will actually help your car in the long run. You also want to be sure that all the rings are sealed completely before you start adding thinner oil...

Just my $.02

 

This has been discussed many times on the forums...

The way I see it is like this - you aren't gonna ruin your car going synthetic right away - but since so many folks (including Nissan engineers, technicians, car nuts, etc.) recommend the complete breaking in of rings/seals/etc. for about 10-15k miles, why not just wait and be safe. Going synthetic before your car's midlife crisis, prior to 40k miles, usually yields the same long term effect - so really what's it to ya to be safe and go synth at about 10-15k miles? You have more to lose if something does go wrong in an early switch, versus less to gain by switching early as opposed to at 15k.

I'm personally at 14k and waiting for my next change, 15k. I'm going with Motul 8100 X-Max 5w30. Some of the best and ester base synthetics out there. Nissan has already stated that ester oil works in our VQ motors best.

 

It has been discussed many times before. Synthetic oil is not thinner. It holds particles just the same. People that continue the OWT of waiting just don't know what they are talking about.

I'll remind you again, that BMW, M-B, Porsche, VW, Audi, Corvette, Ferrari, Lamborghini, Maserati, among others, ALL come with synthetic from the factory. I just suppose those engineers are just throwing caution to the wind and risking the reputations of their prestigious brand images by doing something as foolish as putting synthetic oil in a brand new car.