There is a thread that states The rotella 15w40 is still the old formula if it is sold by the drum. i can't verify this and still add gm's eos even though the engine in my truck was rebuilt over 20 years ago.Heck and I am thinking about trading my 10 year old work truck,but, the felling passed when I found out how much extra the insurance would be.
Interesting. Think this applies to the 5 gallon drums of Rotella they sell at Advance Auto? I usually stock up on gallons when it goes to $11.99. The 5 gallon would be quite a hassle, but extra zinc would be worth it.