Decided to do an oil change on snow blower, an old MTD 2 stage 5hp Tecumseh. I wanted to use up some oil that I had on the shelf, so it got about 1/3 of its capacity from each of these oils: PHM 5w30, Castrol HM 5w30 and ST 30w. I know, time to ask now after I did it, but no biggie to change it out if it's not a good idea.