Originally Posted By: hallstevenson
Fact is, the additives that are in engine oil can and do have a shelf life. No one here knows what that time frame is. The lame argument that "oil" is millions of years old doesn't apply to a formulated product.
Only partially true hall, I'm leaning more with the earlier arguments about the new oil specs coming out in relatively short periods of time- ~5 years.
Without starting any debate whatsoever other than to answer the OP's question, it's like trying to "prove" how old the earth is, or the theory of evolution. Since nobody was around that long ago to watch and document any of the suspected changes up until present date, it's impossible to scientifically evaluate those theories. Just like honestly answering the question of how long a sealed container of oil will be good. Let's answer it this way, since this is my theory- with today's plastic jugs, automobiles as we know them will be gone long before that oil "goes bad".
My take on Chevron's date coding? It's purely a marketing move, to make people who are skeptical to begin with buy more oil because they will think it's "spoiled". That's it in a nutshell.