I was looking in my maxima owners manual the other day and noticed that it preferred the oil viscosity grade to be 5w30. I've been using 10w30 for as long as I can remember, since I live in Texas and it almost never gets below freezing here. Is there any reason I should want to use 5w30 over 10? For my climate either one is acceptable, but which is better...

 

I would think it would be best to use what the nissan recommends. Check out the fluid section of the forum.

 

1030 would be acceptable for your climate area....however to get the best gas milegae nissan recomends 5w30

 

what about if you have a high mileage engine. I've got 225.000 miles so I was told a more viscous oil would be better. I use 10-30 also and Ilive in SOuthern California. Should I be using 5-30 too

 

I mean honestly there are so many variables involved with each car I really cant tell you straight up. If you car is leak free, well maintained even at 225k I would mostly likely run the 530. Yet, oil thins out as the engine gets hotter so most people suggest a thicker oil for the hotter climates to compensate. I guess with this one its to each his own ....You absolutely not harming your car by using 1030 but supposedly your gas mileage will dip slightly.

 

I use 10w30 in the summer because it gets past 100+ F here which means that engine temps will be beyond the operating range of 5w30.

 

Tx = 10w30 is fine all year. The owner's manual has temp ranges along with the viscosity recommendations

 

yet someway in this mystical universe 10W30 is included in 5W30... so your statement has absolutely no logic to it.

as far as high temp is considered they are both up to 30 viscosity resulting in the same high temp performance. 5W30 just has a wider/lower range for cold. So why not use what the engine was built for?

please inform me if I am wrong and I will humbly concede.

 

I've been using 10w30 in the winter and 10w40 in the summer (both non-synthetic) since the car was new. It now has 202k miles on it. The temperature around here has been as low as -10F and as high as 105F or so.

Supposedly synthetics oils tend to be thinner than their petroleum counterparts. A friend of mine is running 0W20 synthetic in his Mazda 3 (sounds crazy to me).

 

If two oils have the same viscocity rating, how is one going to be "thinner" than the other?

 

Mobil 1 run on the thinner side of its viscosity ratings. When measured in centistokes, a 30 weight oil can run in the range of 9.30-12.49. Mobil 1 xW-30 is 10.2 cSt and Amsoil Xw-30 is 11.2 cSt.

http://www.bobistheoilguy.com/visc.html

 

no, you are correct. I believe I was confused reading around about the max operating temps for certain engine oils.

I should say that I could opt for 10w30 since the temps in CA never go below 0 F according to the FSM

 

Check out bobistheoilguy.com and make your own conclusions. You can get very granular on the benefits of each viscosity rating compared to each other. I think you can boil it down to this: 5w or 10w doesn't matter as long as you use a synthetic oil. Finding the right brand is the key. Personally I use M1 0w-40.

 

Living in Alaska I use 5w-30 AMSOIL year round. If your getting about 100 degrees go to 10-30 like the graph shows. But yes 5-30 is recommended and I highly recommend AMSOIL! It outperforms MOBIL 1 PERIOD! Allthough Mobil 1 is a good oil compared to conventional oil. But for the price you pay of Mobil 1 why not get AMSOIL for a buck more. Find out the benefits at the AMSOIL SITE.