"滑油粘度" can be translated as "lubricating oil viscosity" or "engine oil viscosity" (if specifically referring to engine lubricating oil).
"Lubricating oil" is a general term for oils used for lubrication.
"Engine oil" specifically refers to the oil used in engines.
"Viscosity" is the physical property that describes a fluid's resistance to flow.
So, depending on the context, you can choose the most appropriate term.