Re: does using 0w30 instead of 0w20 make a difference?
 

Kinda, but an engine is designed to operate at 100 degrees C these days. The cooling system, oil galleys, oil pump, valve train and rotating assemblies/bearings are engineered to a specific viscosity (cSt value) at that temperature. Rember, flow = lubrication (not oil pressure). Most engines today are designed for an oil exhibiting 8.5 to 9 cSt at operating temperatures. That requires a 20 weight oil for most vehicles. It provides slightly better fuel economy as noted, but also matches with the other systems designed around oil flow and lubrication. (Oil also acts as an engine coolant.)

Oil thickens as it cools. A 5 weight oil at zero degrees C is thicker than a 0 weight oil. At start-up, thinner is better since that is where most of the engine wear occurs.

If you are pulling a trailer, or long distance racing (operating your vehicle at extremely high temperatures (120+ degrees C), you might need a slightly higher viscosity oil to provide the correct cSt value at those temperatures.

50 years ago, we disn't control the engine temperature like we do today (for emissions, etc.) Back then the manufacturers recommended heavier weight oils in the summer months and thinner in the winter months, trying to adjust the viscosity at operating temperatures. Don't let someone tell you to chamge oil weight these days.

The colder your ambient temperature, the more you will benefit from a 0w20 oil (Alaska, Canada and Northern U.S. states.) Look at the recommended oil for your vehicle and compare the cSt values of it with the oil you are considering using at operating temperatures and your ambient conditions at start-up.

Re: does using 0w30 instead of 0w20 make a difference?
 

if you read the bottles of mobil 1 0w-30, it says it meets or exceeds the protection of 5w-30 and 10w-30.

Re: does using 0w30 instead of 0w20 make a difference?
 

Probably 0W-30 works just fine but, again, why use anyting not listed in the manual? In the unlikely event that you were to have an engine fail and Nissan asked you to provide receipts for oil changes, if you aren't able to provide evidence that you used what they recommend it could give them wiggle room to deny a warranty repair. Nissan would have to accept Mobil's claim that 0W-30 is the same as using a 5W-30 oil but that could end up putting you in the middle of an argument between two companies.

Also, oil companies use viscosity index improvers to get an oil to be multi-grade. 0W-20 has a range of 20 points, 5W-30 has a range of 25 points but 0W-30 has a range of 30 points. I can remember back in the 70's that GM had a big problem with bearing failures when people used 10W-40 in their engines and GM had warning out about using it because the viscosity index improvers used to get that 30 point spread weren't providing protection.

That was a long time ago and I'm sure Mobil1 has made many adavances in oil chemistry since then but what do you stand to gain by using 0W-30 over the recommended grades?

Re: does using 0w30 instead of 0w20 make a difference?
 

^well, if 0w20 was available in the 5 quart jugs, I definitely would go with that. I'm pretty confident for the regular driving I do, 0w30 will fully protect my engine. I do think you are giving Nissan way too much credit for "designing an engine to use 0w20". my manual from my 2007 says to use 5w30. it wasn't until later revisions did they say to use 0w20. The NAH has the same engine as my last car (sentra se-r) and that was 5w30 also. I do think for hybrids, using the 0w has an advantage due to it's lower viscosity during startups.

FWIW, I go to Clay Nissan in Norwood and the guy who did my oil change said I was the only person with the hybrid that uses the synthetic oil.

Re: does using 0w30 instead of 0w20 make a difference?
 

for those that use 0w20 since it is a synthetic oil how often do you schedule your oil changes? my dealer said it was fine every 5000 miles with 0w20.

Re: does using 0w30 instead of 0w20 make a difference?
 

Yes, 5000 miles is what I do with my 0w-20 synth.