Hmmm, I'll be up for an oil change next week or so. What should I pour out of my stash? The past few fills have been a mix of Mobil 1 5W30 SM and 15W50 SL (red cap stuff). But I also have PZP 5W30, Rotella T Synthetic 5w40, Maxlife Synthetic 10W30, and not to mention a vast supply of the old 10W30 Penz. Synthetic (w/ Pennzane
). I've been going 5k miles or so.