Manual transmission oil change

[Alisobob]

My MB service manager, hook me on to Royal Purple products 14 years ago

Hahahaha!!! The purple dye they use is just that, purple dye. It does nothing but make people think something special is going on.
Try using non M/B spec RP in a warrantied Mercedes and have an oil related failure and see how far you get with the repair bill. That service manager will deny ever speaking with you! List which RP oil your using.....

[map]

Sorry, I don't understand your point. All coloring in automotive fluids is from dye added. This company chooses to dye the oil purple so it can be indentified. Granted, the purple means nothing more than adding yellow/orange/pink/green/etc dye to radiator fluid.

That's where, for lubes, a combo of weight grade and API certification comes into play... finding a fluid that meets/exceeds factory specs.