This whole forum could be retired and everyone who really doesn't know what to do could take the "canned" advice to just: 1.)Only use full synthetic if required by MFG OR if operating in extreme temps OR if you want to do an extended OCI(unless you conscienciously want to pay more for the full-syn but plan to stick to MFG OCI) 2.)Use the dino or blend of your choice and change at the interval recommended by MFG & a quality filter 3.)Use the weight recommended by MFG excpt in cases of older, out of warranty motors that you must use a thicker oil in to stop consuption or to build pressue 4.)Use HM oil for motors that "need it" (leaks, noise, etc.) 5.)When in doubt use Pennzoil (I had to throw that in since folks love it on here :)) 5.)If still in doubt, do UOA and you have more time & money than I do my friend! I am sure I left something out but it is a good basic set of rules maybe?