Whats hte preferred oil that everyone is useing?

 

Been lurking over at www.bobistheoilguy.com for the past few months. Given the feedback I've gotten, I'll be swithching to Mobil 1 5w30 or 10w30 synthetic when I hit 7500 miles. My goal is to go to a 7500 mile oil change interval, and I will perform oil analyses at 5K and 7.5k to make sure that my plan won't do more harm than good.

I have 4500 on the odometer now so will have results by June/July.


'03 G35S Desert Plat

 

I'll prob be useing Royal purple when its time to do an oil change

 

Free oil changes from my dealer for three years using Valvoline 5W-30

Hoot

 

This question has been on my mind, because I'd long intended to folllow the large volume of advice recommending Mobil 1, but have since learned that Infiniti does not recommend synthetic oils for the Coupe. The Sedan has some leeway, but it's strictly mineral-based for the Coupe, which throws out most of my research.

So what mineral-based concoction should I be putting in my Coupe? I'm at a little over 1000 miles now, was thinking I'd change it out at 1250.

-Jack

Black obsidian / graphite '03 Coupe premium nav

 

On Bob's site, when discussing conventional oils, the two always recommended are Castrol GTX and Pennzoil.

I ran Castrol in the two cars (Altima and 626) we had before and they went 160K and 180K with no engine problems and no oil consumption. And this was before I became obsessed with oil changes, usually changed between 4K and 7K. Got rid of them because I never serviced tranny fluids, so naturally, the trannies began acting up.


'03 G35S Desert Plat

 

JDMan

Castrol Syntec is mineral oil that's ultra-refined to remove impurities...basically we call it, hydocracked oil

 

Where did you learn that Infiniti does not recommend synthetic motor oil? The manual for my 2003.5 sedan only says to use a mineral based oil. It makes no mention of synthetics. Does anyone know why the coupe would be different? I wouldn't think the coupe's motor would use seals different from the sedan's.

FWIW, a review of the MSDSs for various oils shows that Castrol Syntec and Valvoline Synpower use mixtures of solvent refined and/or hydrocracked hydrocarbons as well as polyalphaolefins (PAO) in their base oils. Mobil 1 appears to be based entirely on PAO. PAO is synthesized from ethane or ethylene that comes from crude oil refining processes. PAO also can be made from methane, natural gas, but that is just another hydrocarbon.

If Infiniti does not recommend synthetics they may be refering to oils based on esters or glycols or some other exotic.

<font color=blue>Dan</font color=blue>

 

G35 Coupe manual only recommends mineral based oils. No idea why though - cause it doesn't make sense that the seals would be different. It's a Coupe only thing.

 

https://g35driver.com/forums/showfla...sed&sb=5&part=

We scanned in page 10-5 for both the sedan and the coupe

 

I looked up the 350Z owner's manual online and it says the same thing. Mineral based only.

Maybe it's not a seal issue - it might be a cylinder liner or something like that. I dunno....have to admit it seems a bit counter-intuitive. Synthetics supposedly offer better protection, better resistance to heat, stay cleaner longer and don't break down and should be perfect for a hi-performance engine like the Coupe/Z and yet synthetics are not recommended by the factory only mineral based oils.

I haven't hit 5K yet on miles so I am still using mineral oil till the engine is broken in fully. Haven't decided if I feel like totally going against the factory recommendations or not. Sure seems strange when other high performance engines like Porsche's and Vette's and others are coming from the factory with synthetics like Mobil 1 and their manuals are recommending nothing but synthetics.

 

Infiniti does not recommend synthetics b/c some synthetics have properties that over time can eat at the silicon seals on the Infiniti engines. That was the general consensus from several Infiniti dealerships that I called. The manual does recommend Petroleum based oils. If synthetics are used, some infiniti mechanics recommend Amsoil or Mobil 1, Royal Purple.

 

Yesterday I went to infiniti to get my oil changed, and asked for synthetic, The service manager didn't discourage me from getting it. I think its safe to say if the dealership's service shop is doing synthetic oil changes then its good for the car.