Bump for useful info

 

The main reason for changing oil is to get rid of combustion byproducts building up in your crank case and oil pan. Whether you use conventional or synthetic oil makes no difference. Synthetic oil might take longer to break down but that doesn't matter since gunk is still building up in the oil. Change your oil every 3k miles, period.

 

but they're sayin' the gunk doesn't cuase more wear... but i'm guessing the gunk makes you lose hp... BUT changing out the gunk DOES cause wear... ooooooh

 

My dad always changed synthetic oil vehicles at 5k miles. He always told me to do the same. I never really questioned it because he has a pretty good background in automotives. He still changes out regular oil between 3k and 4k miles but he has sometimes let synthetic even slip to nearly 7k miles before changing it. I have been rather consistent about changing my oil every 5k miles. I take the manual saying to change oil every 3k miles as more a rule of thumb than a standard operating procedure. This study just goes to further reinforce what my father taught me. go dad