I've been on here for a while so I have read many posts extolling the virtues of synthetic oil, with countless opinions on the major brands superiority. After reading through the owners manual a while back, I noticed that it specifically states our engines are designed to operate on conventional motor oil. Synthetic oil is not recommended.

Can anyone provide insight in to why so many people are contradicting the recommendations of Infiniti? If there is a logical reason for people switching to synthetic, I'd like to hear it. If they DID recommend it, wouldn't the car come from the factory filled with synthetic?

On another note, I see no indication on tranny & rear diff compatibility with synthetics. Any thoughts?

Thanks in advance...

 

I've ran synthetic for 40k and I've had 0 problems. I think its a scheme to get people to go to the dealership to change oil every 3000 miles honestly. For tranny you have to just use Nissan Matic-J and for differential i've seen people run synthetic but I just went with nissan anyway. I dont see why synthetic motor oil would be a problem if infiniti dealerships offer that service as well. All high end cars are using synthetic now, so that says something about that technology.

 

I'm pretty sure the nissan OEM diff fluid is synthetic. I just replaced mine at 34k with Redline 75W90, which is a full synthetic. If you have a sedan non-sport, or the G35X, you could use Redline 75W90NS.

 

I've run mobil-1 5w-30 synthetic in my camaro for 122k miles and I've never been low on oil or had any wear problems. So I decided to run it on my '03.5 sedan. I haven't experienced any problems with it either.

 

I run M1 15W50 syn but I need it for the extra heat protection. My car is not the norm. You are fine either way but can go longer between changes with syn.

 

I am running syn-blend oil until I get to about 30k. I was told you need to let the engine break in. I think its BS or I am I wrong in thinking that?

 

I switched to full syth motor oil at about 12K I think... no problems - the dealers I go to have no problem with it... Some even offer it (WC Nissan uses Motul and Tustin Infiniti will fill with synthetic, but I'm not sure what they use, M1 I think)... I've used M1, RP, and Ams... I prefer Ams... Gear oil I've used M1 and now Ams... will try Silkolene in a few thousand miles (new Quaife)... Trans - I always use the OEM recommended Matic J... That's the only time it is actually clearly written that anything else could void your warranty.

So synth motor and gear oil are fine... what type? - you could read for days and never find one that universally is accepted as better than another. I like AmsOil though.

Stick with Nissan Trans Fluid for sure.

Oh, almost forgot - break in period for switching to synth motor oil... It is a good idea to break in with conventional oil to let the seals set... It is said that running syth too early will cause problems with the seals... I'm not sure what is the "recommended" miles, but like I said I switch at 12K and haven’t had any problems (35K now) knock on wood

 

I've always run conventional oils except where the factory recommends synthetics.

I'm just not really sold that synthetics are a "better" oil. I know they can last longer, but the 3000 miles oil change is really just a marketing tool. I usually send test oil samples to blackstone labs and i was going 5000-6000 miles before testing would show the oil start to degrade.

I recently tore down my 5.0's engine which had been run on conventional all it's life and at 105K miles the cylinder walls still had it's original factory crosshatching.

 

i use synthetic to extend periods b'tween oil changes. i has pit passes to the long beach gp and they use mobil 1 in 900hp methanol powered champ cars. so it should be good enough for my little g.

 

thx boys. i've asked my service centre to start using: synthetic motor oil as i'm going on an extended road trip and it does get chilly here in winters; OEM tranny fluid; and a compatible synthetic for the rear diff. i'm only at 54K kms (33K miles) but as i'm not the original owner i figured changing these fluids would be a good idea.

 

^been using synthetic in mine since 3k kms. Synthetic in diff and trans(MT) Now have 29k on car.

Nissan AT fluid is synthetic.