Originally Posted by hyunelan2
Contrary to some common beliefs, dealer's don't make a lot of money from selling new cars. They make a lot of their money from servicing them. Open the owner's manual of your car, it will have manufacturer recommended oil change interval information in it. Usually this interval is much longer than the dealer tells you. The dealer's service department wants you in the door more frequently. If you go the recommended 7500 miles between oil changes, that's only 2 oil changes in 15K miles, where they could be billing you for 5 oil changes if you go in every 3K miles.
dealerships are not repair shops. their bread and butter is low level workforce, short time, high volume items like oil changes, belts, etc. higher profit margin. just like teeth cleaning by your dentists. they hire a bunch of entry level folks and tell you to do it every few mths. or the infamous wisdom teeth. let us pull'm out!
no one in sane mind switches an oil taker to synthetic. every car i buy, and i buy used, is tested for oil consumption. in 2-3 000 miles, you know well enough if it's a candidate for synth, or not. if it takes oil - it's a no go. adding oil is too expensive. we have a 95 eclipse in the family that i will never even get close to synth. but the rest of our cars, and my son's cars - synth only. i do amsoil, he does royal purple, his choice. works great.
otherwise, if you do your oil changes with synth every 15 000 miles - and i do sleep well with that - it is cheaper than to do 5 000 miles with conventional oils. and that is not even the point. the point is - synthetics are plain better lubricants. BMW is not dumm to request synth oil in their engines. best i know, virtually all new models come with synth in them. thereafter, end users start justifying, usually based on $$, this or that.
alot of this is habit, stubbornness, fear, even cultural or reginal inhibitions. y'all know well enough there are chevy and ford areas in the country, or asian ones. i can tell you, from working in five states, that redneck in AL is driving a beat up Chevy or Ford, redneck here in Pacific NW - beat up VW or Civic. even better - an Opel. same goes for oils.