Happens like clockwork. At this mileage there's a noticeable acoustic change at idle and low rpm. It goes from butter quiet to more metallic. Is this mileage at the point where a particular additive takes over/stops working?
Factory OCI is ~13k miles. Oil is Castrol OE 5w30 LL04.
Factory OCI is ~13k miles. Oil is Castrol OE 5w30 LL04.