Rotella 15W-40

The oil might last forever, but there is no telling about the man-,made additives in there. Those chemicals might deteriorate over time. How much time? I doubt if anybody really knows, it is just guess-work.
Come to think of it, when (if) oil "breaks down", what does it become? Once those long-chain molecules are broken, they are not "oil" anymore. What is it?

I buy my own Chevron Delo 400 oil at Costco (about $13/gallon in a 3 pack), and a NAPA Gold (Wix) filter, then take it to Masterlube. They charge less than $30 to do the oil and filter change and check all the fluid levels. It is worth it to me to not have to crawl around under the truck, then have the dirty oil to handle.

Branson N Tucson wrote:
For those that change their own oil, Sam's Cub,a case (6 1 gal ) $15.00 off, 65.00 a case.Pick up case yesterday good thru July 17th.

Yes! This is a good deal. This oil also works great for Onan gennys.

"Come to think of it, when (if) oil "breaks down", what does it become? Once those long-chain molecules are broken, they are not "oil" anymore. What is it?"

Sludge. When heated, oxygen combines with the broken oil molecules and they develop properties similar to the binder in oil based paint. They eventually harden and stick to the inside of whatever contains them. It's truly lovely, but, you don't get your choice of colors.

Chum lee

If you are that worried shake them up once a year until use.
There is oil out there that has probably been pushed to the back of the shelf for many years as new stock is put on shelves.

If you go to the website you can order this oil and have it delivered to your house with FREE shipping.
I have never seen an expiration date on any oil that I have bought. :B