Select Costco Locations: 2-Pack 5-Qt Kirkland Signature Full Synthetic Motor Oil Expired

Actually the variance is still there. These cheap entry-level synthetics are basically your conventional oil additive package and VM in a Group III base oil.

A traditional premium synthetic has a high performance additive package that meets usually ACEA and Euro OEM specs and uses a better VM that burns cleaner. They also tend to use a better Group III and and/or PAO (Group IV).

You have to understand how these products are made, the Kirkland (Costco), Amazon Basics, and Supertech (Walmart) cheapy syns are all based on a bid in this case Warren won the bid with the lowest cost product. Hence you get just the bare minimum in engine oil, so a skimpy conventional additive packages (8-9% treat) and cheap and dirty VM (OCP). The goal with formulating these products is to make it as absolutely cheap as possible or you don't get the bid.

When premium brands formulate their synthetics (Mobil 1, EDGE, Platinum, Liqui Moly) their goal is to differentiate so when you see 10x better wear protection or sludge prevention it is in comparison to exactly these market general cheapy products as those meet the bare minimum specs. Your premium syns will use a higher end additive pack (13-16% treat) and a clean burning, shear stable star polymer. They also tend to use some higher end base oils like GTL, PAO, esters along with GIII. These also tend to meet ACEA and a lot of the harder Euro specs like Mercedes, VW, etc. This is why you don't see a Kirkland 5W-40 for a VW or Porsche as those products can't meet the tougher specs.

The reason people seem to think they are all the same is they never take apart their engines to see the difference. The higher performance oil will keep your engine running closer to new for longer where the cheap products leave more deposits, sludge, and cause more wear. Your engine will still run, but it will burn more oil and have less hp (clogged piston rings) and likely shorten turbo life as those bearings hate deposits.

Here is a little more proof, most of the big lubricant marketers have introduced their own cheapy syns for fighting grade synthetics to compete with kirkland/amazon/supertech. Mobil has Mobil Synthetic (no 1 in that name) for example. Look up the specs and it's just API SP/dexos1 and is likely a market general cheap formulation just like the others. Mobil 1 however is a different beast and is self formulated by ExxonMobil and still has a nice slug of PAO in the products.

Now if you get into higher variants, I'd agree HM, EP, SUV etc the variance there is much smaller. They might have a little booster or be a smidge thicker but very similar to each other.

My suggestion is to compare specs. If they only meet SP/dexos1 then they are basics. If they meet Porche, VW 50x, MB 229.x, BMW, ACEA specs then they are high tier with robust additive packages.

I used to run Sequence IVA tests (a fired engine test to approve an oil for API SN) on my basic packs as well as my premium stuff. If you're talking about Project Farm he's running something more like a gear/scuff type test. We used actual OEM created tests in real engines.

SWRI Seq IV wear test [swri.org]

UOA is useful but doesn't give you the full picture, for example darker oil doesn't mean it's bad as higher end oils have almost double the dispersant which means they solubilize more contaminants, crappy oils will leave more behind in your engine and sumps.

BTW I used to make these types of products and run all OEM/API/ACEA testing to get them approved.

I don't think I'll convince people like you who think cheaper is better, but the truth is they are different products. A McDonalds hamburger isn't the same as one from Shake Shack, the ingredients are just different and your engine is just like your body, the bad stuff leads to deposits, clogs, wear etc, but it happens slowly over time.

As an ex formulator it pains me deeply when people say "oil is oil" it's like telling a chef that soup is soup because they all use water...

The Shell GTL "oil" for instance has proven to improve deposits on a Sequence IIIG test with the same additive pack over the regular Yubase Group III.

As a time traveler I have specifically come back from the future not to make loads of money for myself in the stock markets or to stop a horrible accident from occuring. No, I have traveled back to let you know that indeed this motor oil will go on sale again in 6 months, and the price will be the same. But also if I were you I wouldn't stock up now because you probably won't be getting a chance to use the oil anyway. As to why, I cannot tell you or I may tamper with the space-time continuum.