motor oils

[Boog]

What is up with today's motor oil ratings?
For over a year I have found our Walmart isn't stocking a full line of oil like they used to. Right now they mostly have full synthetic in 0w20 or 5w20 "made from natural gas" on the shelf. And what's more, it is labelled for high mileage engines.
It has long been my understanding that the low first number is for cold weather startups and the second number is for full operating temp viscosity. And a heavier rated oil in the past was recommended for higher mileage engines.
Are they rated differently these days? Even on our modern engines 0 or 5w20 sounds too thin for good protection to me.
I'm changing oil in my 2003 Tahoe with 300,000 miles on it. Surely there is enough wear in it that a heavier oil would be of benefit to it. That truck sees over 100 miles of highway every day.

[yuccales]

Was checking out my sisters new Subaru the other day. 0-16wt oil! Gotta be like water! The local Napa and O'Reillys has a huge selection of oils in weights I've never heard of. 30wt, 10/40, 20/50 used to be the norm.

[weq92f]

.

Problem with NAPA and O'Reillys is their price gouging. Outrageous prices for just about everything on their sales floor, including motor oil. Wal-Mart is my goto for lubricants and other common automotive needs and shop supplies that they carry based on price alone.

Example: Wiper blades. O'Reillys wanted 50 bucks minimum for a pair. Walmart sold me the same thing for 25 dollars.

-Kevin

[Tom]

Low weight oils for modern cars. Run what you want. My 300k suburban calls for 5-30. I use 7.5-35 by mixing half 5-30 and 10-40 lol.

[Getter-Done]

Yeah these are not the numbers We grew up with.

I guess the Smart people changed something.

Here are 2 videos about this stuff.

The W is not for Weight.
I have heard Weight all my life.

Engine Oil Codes Explained, SAE (Society of...

Motor oil viscosity grades explained - YouTube

[mongocanfly]

My truck calls for 0-20.. they told me to be sure to use that,but to change it every 5000 miles instead of 7k when the change oil light comes on

[Boog]

The owners manuals, as far as I can remember, have a graph with oil weight recommendations for the climate the vehicle will be operated in. The lowest number to be used in the coldest temps for easier cold temp lubrication. I don't think I've ever seen a zero recommendation.
As far as my old 315,000 miles Tahoe is concerned, I have used 10w30 in it for 12 years and now with the high miles it does use a couple qts between changes. I am thinking a 20w50 might be a good one to use. Might even use a bit less oil too.