Since synthetic oil is a little more expensive, I was wondering what your intervals are for changing synthetic oil? My guess is every 6000 with a filter change at 3000. Does this sound right?

2003 G35 Coupe 6mt Diamond Graphite

I personally do both at 3000 mi. I know you probably dont have to but there are a lot of things that I do that dont have to be done. I recently went on a 1000mi road trip so I'm gonna let the oil go to 3750 for the first time. With synth and moderate driving I see no reason why you cant get 4-5k out if the oil but I dont wanna risk it. I spent the loot for the car I'll spend the loot for the upkeep.

Go to maxima.org and do a search. There are some members there that have been sending in synthetic samples to some lab for analysis after progressively longer oil change intervals. They were up to 8,000 miles with minimal contamination when I last looked. I run Mobile 1 5w30 for 5,000 miles in my Maxima, then change both oil & Nissan factory filter. My Infiniti dealer offers free oil changes for the first 24,000 miles, is this standard with all Infiniti dealers?

someone mentioned sending a sample of oil somewhere on this forum, but I couldn't find it. Is there a place around Orange county that does this?

2003 G35 Coupe 6mt Diamond Graphite

No, it's not standard practice for Infin dealers to give free oil changes up to 24K miles. But it'd be nice.

As to oil changes, for me synthetic after 10K on odo, changed after 5K miles, and change out at each oil change with Nissan filter. If someone would "move" those posts from a Nissan forum re lab tests showing synthetic is still good after 8K miles, I'd like to see them. Probably won't convince me to wait for 8K miles to change oil, but it'd be nice to see.

As to changing filter only, that's not for me. But I think Amsoil actually recommends it. Maybe there's something to it, but I've never heard it universally recommended by Royal Purple, Kendall, Pennzoil, Mobil One, Castrol, or any other synthetic oil manufacturer. Nor, have I ever seen it recommended by a magazine or testing lab or car manufacturer. If it's out there, it'd be a service to all of us if someone would paste it onto this site and others! It may not change anyone's mind, but it would give some comfort that if you go 500 miles over ______miles, you're not doing serious damage to your engine or shortening its lifespan.

BONDg35c

I changed to Mobil 1 5w30 at 7500 mi with a stock filter (shorty). I plan to change my oil around 4500mi thereafter. I've noticed an increase in gas mileage from switching to synth from dino.

My oil guy talked me into 10w30 instead of 5w30. Whats the difference?

G35Coupe B/B 6MT Aero/Premium

10w30 is better for warmer climates.
the lower the first #, the better it protects when the oil is cold.
the higher the second#, the better it protects when the oil is HOT (such as in racing conditions you would need 10w50 or so).
Mobile1 also makes 0w40, which is widely used in most Mercedes engines.

<font color=green>-Rambo</font color=green>
G35c 6MT DG/Willow/HyperGround/BorlaExhaust