Engine oil: synthetic or mineral based?

[jho75]

I have owned a 2004 G35X for almost a year now. My sole trip to the dealer was to have a rear wheel bearing replaced (at about 78,000 km, which I found odd), and at the same time had the transmission flushed (expensive, but perhaps preventative). At that time I questioned the service manager about synthetic motor oil. He suggested that Mobil 1 would be Nissan's first choice for synthetic. Thinking back to how much better my previous Acura Integra (4-cylinder) ran on synthetic, I switched over to synthetic in my Infiniti. Haven't noticed the same noticeable improvement. Should I go back to mineral-based oil? Does synthetic promote leaks and oil useage? Any input will be greatly appreciated. Thanks!

[joe603]

Welcome to NICO!

Ahh, the oil debate! Here's my advice, if you're going to use synthetic, use a "real" synthetic. Mobil 1 is a blend of Dyno and synthetic oil. Royal Purple and Amsoil are true 100% synthetic.

Mobil 1 might be that tech's choice, but it's not Nissans. (they have there own, ester-based oil).

[G_whizz]

I thought once you made the switch you couldn't ever go back??

I've heard nothing but good things about Royal Purple.

Welcome to NICO!

[joe603]

The issue is with older cars. If you run Dyno oil, some of the seals absorb it and it has the effect of expanding the material. Now lets say you've used dyno oil for the life of the car...maybe 80k miles, then you switch to synthetic. Now those engorged seals will shrink due to the properties of synthetic oil. This is what started the idea that switching to synthetic causes leaks.

However on modern engines, those seals rarely expand at all, so switching will not cause a leak. We're talking about older engines like the Chevy 350...not the VQ35.

Check out the oil bible for more info: http://www.carbibles.com/engineoil_bible.html

[Tampa G35 Sedan 6MT]

I use royal purple and it makes the G run Great!

DJ

[tollboothwilley]

I also use Royal Purple, its great if you are in the upper RPMs often. Otherwise, its expensive and probably overkill. Its good stuff.

[SVTCOBRA]

Have been using Mobil 1 Fully Syn for years!!!!

Mobil 1 folks tell me there is no DYNO juice in it. Pick up the phone, give them a call. I did.

Change my oil every 3k to 3.5k miles & use Nissan filters.

Was considering switching to one of the other synthetics UNTIL I saw the inside of my 05 G Sedan engine! Had an internal part fail (possibly an o ring) and Infiniti had to crack it open to fix. Fixed under warranty. The mechanics were even impressed with how clean it was!!

[BrandAidDesignG35]

I had been using M1 for the first year and a half, I went out on a venture to test a few others.

Amsoil, Castrol, Cheapy stuff, and next will be RP, if not overly impressed, may go back to M1... Of the others I've tested I really will say that Amsoil is great, very smooth, fast revs.

I have some oil consumption - 1-2 quarts between change intervals, obviously depending on driving style. I do drive pretty hard though.. sometimes. I got a speeding ticket a few months ago, funny thing to mention, since I got the ticket, I have been getting upwards of 27mpg, which is nearly 10mpg more than I used to get driving irradically.

[Tampa G35 Sedan 6MT]

Grant... Just wait until you try the RP...

Oh and I bought it on sale 30 bux for 5 qts and a m1 filter

DJ

[Q451990]

There is a whole huge forum on oil. Do a google search for "Bob oil forum" and you'll find it. You can spend hours there, know very little more than when you started, and have a major headache!

I can say that RP is not particularly well regarded by the oil gurus there. I personally run M1 in both the G and Q. The truck is "new to me" and has M1 in it from the former owner. I'm taking advantage of Pennzoil's $15 rebate on a $20 five quart jug for their "Platinum" full synthetic. The Frontier has enougn oil stashed away for several years at $1/qt. Can't quite cut the M1 cord on the rest of the fleet yet - but that price is attractive!

Heath

[Tampa G35 Sedan 6MT]

Why do you say that about the RP...

I think everyone here likes RP... They don't like the price but if that wasn't the issue they would use it.

DJ

[Q451990]

I was just commenting on what I have read in another forum... apparently based on used and new oil analysis. That said, there are some RP fans there too.

Heath