So why would they put that if its just Hydrocracked?? What is the alternative explanation? Customer: Mr. Ford why did the back of your bottle say its part synthetic? Is this really true? Ford: Well Mr. Customer, we were trying to save money and since we already had a bunch of labels printed for the 5w20, we just pasted them on the 5w30 bottle, but we didn't think anyone would notice. I would say that as far as the makeup of mc5w30 , its definitely faith and interpretation. It does work well though.