yea ive always used Castrol and change my oil every 2-3 k miles. I just want to cut down on time and hassle mainly. I dont understand how it could work. If you get dirt in your engine it needs changed. A friend of mine works on road construction and met a guy who has a small truck that had over 340,000 miles on it and he ask him what kind of oil he used and he told him amsoil and changes it every 25,000. I know its very expensive but if it actually worked It would save time and money.