Just wondering for a couple of reasons what kind of motor you guys use in your koler engines. I had some trouble with mind droping lifters a year or so ago. I was using 10w40 valveoline. Then my dealer's mechanic told me to switch to rotella oil 15/40 . I've been running that ever since. I change my oil every week and oil filter every other week. So as you can see I use a lot of oil in 4 mowers. I want to buy my oil in a 55 gal drum this spring and I'm thinking about changeing. Rotella is almost twice as much as valveoline. Don't know if I'm spelling that right or not. Eric and you guys tell me what you use. Tell me what you use in your pumps. Dixie calls for 15 40 so I use rotella there too.