What is GM eos- and is it sold as something else in a parts store ie Napa Autozone??? The last engine I broke in I used John Deere "Break In Oil" 15w-40. JD uses this in all new tractors and combines for the first oil change interval. Worked well for me I ran it for the first 500 miles. No oil usage post breakin period. Just my 2 cents from a farmboy.
