Oil questions

I have a 2005 Nissan Altima. It has just over 124,000 miles. I drive around a lot. Both in the city and on the freeway. What weight of oil should I be using in my car? Also, is there a brand of oil that stands out above the rest? I live in Riverside, CA for anyone who wants to get an idea of the environment that I live in since I know that affects what types of fluids I use. Lastly, I have been using full synthetic oil for years because I liked the idea of not having to change my oil every 3,000 miles plus I heard that regular oil leaves behind a lot of gunk. However, until recently, I heard that regular oil is best for my car unless otherwise specified in my owners manual. What’s the truth about the matter?

Read Manual. Use weight that manual says. Any brand of oil is fine. Syn is good for extreme conditions but has no affect on oil life. Change oil at recommended intervals. Fresh oil/filter will ensure long motor life.

Stoveguyy pretty much covered it. Synthetic might be a bit better, but regular oil is fine if that’s all your owner’s manual calls for, so I wouldn’t spend the extra money.

Synthetic oil should not be used to extend time periods between changes. Synthetic oil is just as subject to dilution by “blowby”, contamination from combustion byproducts contained in said blowby, and collection/suspension of particulates from normal wear as dino oil is.

Synthetic is chemically the same as dino oil, but contains fewer contaminates and has more consistant molecule size. That makes it withstand extreme temperatures better while maintaining its lubricating capabilities better under extremes. Therefore it hold up better to turbochargers and high stress applications.

Bottom line, if your owner’s manual says “synthetic required”, than synthetic is required. If not, dino will keep your engine running fine forever. No evidence exists that synthetic will extend the life of a properly maintained engine that does not require it. Lots of evidence exists that a properly maintained engine will last hundreds of thousands of miles (assuming no design or manufacturing errors) wil dino.

Extending the time between changes because you’re using symnthetic IS however an error. And that practice may cause premature engine demise. The oil removes heat from the cylinders, washes the surfaces, suspends particulates for capture by the filter, and has to maintain a fluid pressurized barrier between key wear parts, like the crank surfaces and their respective bearings. Fresh oil is always better than old oil, and it makes no sense to “push” the life of the oil at the expense of possibly shortening the life of your engine.

05 Altima? Cvt trans? Service any and all trans. Cvt or not. Folks change oil 3times/yr and never touch trans. Not good

Oil is oil–as long as it meets the letter designation your owner manual calls for (SN, etc). The off-brand oil is made by name-brand companies. There are only 3 companies that refine oil in the USA and all the oil comes from them. Flag motor oil from Checker Auto, for example, is manufactured by Valvoline. It’s known as market-segmenting when they sell the same thing to diff people under diff names. The same thing happens with tires, aspirin, beef jerky, shampoo, etc. As far as weight goes, use whatever weight the owner’s manual states.

Plus 1 for Mountainbike and Stoveguy.

Just make ABSOLUTELY SURE that the CVT fluid is replaced with Nissan factory fluid, not some other ATF, or even generic CVT fluid.