I hestitated to respond to this post because I knew that it would end badly. GearHeads and their oil are like women and their doctors, fiercely loyal to their brand. I agree that at -40 conventional wisdom probably should be thrown out with the cat. Otherwise, while interesting, nothing stated here will change my mind especially where the added zinc is concerned. I don't add MMO to my sump, but I use it in my dash pots and in the gas for my antique Gravely tractors. They are at least 50 years old and start up with a pull or two and run like bears after a prospector. The Volvos get a shot glass full in the cylinders for winter storage too. I have 2 Volvos, a Chevy Silverado, a Geo Tracker, 3 antique Gravelys and other assorted power equipment that all get the same treatment. My stuff starts and runs and as far as I can tell never uses any oil between changes.