01-12-2013, 05:53 PM
IMO the "you have to stick with synthetic" is just to get people to spend more money. There is no reason you can't switch back to conventional oil as long as it didn't come from the factory w/ synthetic. Synthetic won't break down as fast as conventional oil so you get longer life. BMW recomends 15k mile oil changes and they put synthetic from the factory. Would I wait 15k to change the oil no but they do that because when they sell a car or lease it it comes with free factory maintenence oil changes so this saves them a ton of money.


