problems with oil ring sticking ... use an oil that tend to polymerization at high temp cause it. changing oil don't help at all. I hear Kreen from kanolabs.com helps.
(having g37 over 120K km, 0 (i mean literally 0) oil consumption, Just avoiding any oil that tend to polimerizate itself at high temp. Simply boil it in a metal can and you see all [censored] appears on bottom. (this thing will accumulate on a oil ring and a compression ring , limiting flexibility and severe problems) as a test, stinky one but works. pennzoil, any kind, pass ... btw
so as i said a changing oil doesn't help, need to cure disease.