What is frustrating about many Safety Data Sheets is that they are inconsistent. This example shows 2 sheets, each showing 2 components. Both oils have ZDDP but only one lists it.
We know they are supposed to list things that are "hazardous" chemicals, yet why are some missing that we know are there?
Polyolefin polyamine succinimide is a dispersant, no biggie. In fact, I would think both oils have that one, not sure though, since there are other dispersants.
Still, there are clues that pop up on Safety Data Sheets, just an incomplete picture at times.
Anyway, the 1-Decene Homopolymer Hydrogenated is the well known PAO base oil, an expensive premium component which helps Mobil1 EP be superior to AC-Delco cheaper oil. ....
The AC-Delco's "Severely Hydrotreated Heavy" ... is just GroupIII base oil, a cheaper kind of synthetic oil.
Originally Posted by Talent_Keyhole
Both oil brands are mineral oils that have been refined and hydrotreated.
Not true. Both are in the category of 100% Full Synthetic. Mobil1 EP has about 1/3 PAO and 2/3 GroupIII base oil components, something like that. AC-Delco has no PAO, a cheaper brew that oxidizes more easily and has worse low temperature properties too.
Often times you'll see the phrase "Fischer-Tropsch" on a base oil component, which indicates its the better GroupIII+ Gas-To-Liquid (like Pennzoil's PurePlus).