Technician A says that an SAE 40 oil has a lower viscosity than an SAE 20W-50 at engine operating temperature. Technician B says that a 10W-40 multiviscosity oil reaches bearings faster when the engine is first started than an SAE 30 single viscosity oil. Who is right?

Question

Quizplus · Accepted Answer

Technician A is correct because the higher the SAE number, the higher the viscosity at engine operating temperature. Technician B is also correct because multiviscosity oils have a lower viscosity at low temperatures than single viscosity oils, which allows them to reach bearings faster when the engine is first started.

Technician a Says That an SAE 40 Oil Has a Lower