5-Quart Mobil 1 Truck & SUV Full Synthetic Motor Oil (5W-20) Expired

As a person who used to formulate these products. No, full synthetic is not full synthetic. You're basically talking about the Group III base oils are the same, then the additive mix is different from each company. Also Mobil 1 still uses some PAO so you'll never find that in any Kirkland full synthetic.

Here is the formulation difference between a

Premium synthetic (Mobil 1, Pennzoil Platinum, Castrol EDGE, those types)
Base oil: Group III and/or IV or V mix
Additive package: Premium at around 13-16% treat rate plus whatever marketing claims boosters (sludge, wear, longer drains etc.)
Viscosity modifier: Expensive star polymer which burns cleaner and lasts longer (more shear stable).

Entry level synthetic (Kirkland, Supertech, Amazon basics, etc.)
Base oil: Group III and now maybe even Group II+
Additive package: Market general from one of the big 4 so 8-9% treat rates.
Viscosity modifier: Olefin copolymer type which burn a bit dirtier and tend to be less shear stable but they are cheaper.

So the first one is formulated to meet some marketing performance claim and was always meant to be a more expensive top tier fluid.

The second one is a cheap meant to meet a bid from Costco or Amazon so literally a tenth of a cent will be cut from those products to get the bid. Hence you get the absolute minimum amount of additives to meet API and dexos1.

As for those specs, there is a window sort of like a test. Getting say an 8.0 is passing and the second group of products target 8.0, and if I got a higher result I'd take some additive out and try again until I just hit the 8.0. If I could make a 7.5% treat additive pack I'd get more business and that's the goal. The first, premium group of products, marketing will ask for a higher target and allow us to put more in to help them sell the product with performance claims. They are more premium products so spending a bit more on additives is acceptable.

Now if you want to go to project farm and cook your oil in a coffee pot to say they are equal... you can but instead I used to run fired engine tests at SWRI and Intertek and get actual deposit, sludge, wear test results and I saw that on my skinny cheap packs vs. my premium packs.

So long answer but no full synthetic isn't full synthetic. Also don't fall for "synthetic technology" that's like "cheese food" has no cheese.

One last note: Turbos hate deposits, it kills their bearings so those cheap, dirty OCP polymers could shorten the life of the turbo.

Except tylonol arthritis has less of a dose and migraine has caffeine so...lol