370Z comes with full synthetic?

Originally Posted by dad

Does Royal Purple maintain its purple color after it’s put into service?

No. The dye that’s used to color the oil dissipates shortly after being put into service. The color will turn brown at some point.
That explains the caramel color he is referring too! No, your correct, it's not cleaning the engine! But it is not because it is not working. It's because the oil was changed way to soon, at 3 thousand miles. RP, needs to go at least 5 to 7 thousand miles to work properly.