In this video, we replace the hydraulic lifters in the NA Miata in order to try to quiet the idle down. Upon removing the lifters we found several that appeared to have undue wear. We prepared and primed the new lifters and installed them as well as doing an oil change. Moving from 10w30 Penzoil to 5w40 Motul also helped keep the valve train quieter after extended driving and to quiet sooner after a cold start.