You will not notice a difference between a thin 30w and a thick 30w. Example: was that i put Valvoline Racing 30w (11.0 cst)in my boat (Ford v-8) and Chevron Delo 30w (12.5 cst) and there is no difference on the pressure guage. I think the thicker oils run hotter because of more friction and work to pumpthe oil and thus it heats up and is the same as a thinner oil. I would rather use on the thin side of the scale and have faster-cooler flowing oil. I use M1 5w-30 in my Jeep and have 70 psi at highway speeds, and 35 at hot idle.