Awesome knowledge and info on oil changes!:great: What about diesels?actually, i have several:
1. re-evaluate your "oil has to be changed at 3000 miles" belief. no, it does not. read manual carefully. what dealer tells you is dealer's job and profit. there are no 07 cars that need oil to be changed every 3K miles, unless you are driving in the Goby desert all the time. search on the internet for a book called "car oils bible", it might shad some light on the 3K oil change. myth
2. i am a firm belever into synthetics. FIRM. engines run much better, oil changes need not to be done as often, less sludge formed. in 2004 i bought a brand new honda cr-v, and put 54K miles on her in one year. based on the 3K theory, i did oil changes every 2.5 weeks, as it was nothing for me to get 1200 miles a week. ergo, i went through every oil they had on the market. until i found royal purple. that was it! it's the best oil out there, i have multiple vehicles, at certain point, all of them ran on RP with fantastic results. if the engine is done right and you have no blow-by exhaust going into crankcase (lord save me from even thinking that chevy could possibly make something like this!), RP will easily last for 10K miles. yes, it's pricy. well, you always get what you pay for. also, you can pay now, or you will pay later. trivial.
3. slowly, i ventured from RP to amsoil. mostly due to the same OIL BIBLE, as guy who wrote it "proves" that it's the best oil out there. ok, here's the scoop on amsoil: my wife's RX300 really likes it. i lost track of miles i have on the last refill, engine runs nice, smooth, and quiet, oil is just dark caramel; i had it in my ranger for some 12K miles, and changed it as engine got to the point of slight noiseness; my honda could not tell any difference; my chevy truck does not like it! it's been only 7K miles on refill, and oil is already dark and i start sensing some noise on the cold engine. so, RP it'll be in few weeks.
of course, i am far from assuming that out of all the cars, chevy's engine has the worst piston rings seal and oil is burnt due to blow-by gasses. that would have been a prepostorous idea!
4. by the way, when i do my oil changes, i do them myself and do flush with flush oil. now that is something that will extend your engine/oil life greatly! i simply drain used one, refill with the cheapest one in the right weight i can find at walmart, and run engine for 15 minutes, with the last 2 at maybe 2500 rpm. then drain it. you know what - comes out pitch black! then i change filter and refill with good oil. beat that, quick lube. or even dealership.
5. use MOBIL1 filter only! it's been proven that it's the 2nd best filter out there. 1st best can not be purchased nationally, as it's made for japan use only.