Castrol's 0W-30 engine oils are all premium full synthetic and are typically designed for use in European performance cars requiring an ACEA specification.
Castrol's full synthetic 0W-30 motor oil has been liquid engineered to flow like 0 Weight oil in winter temperatures, but to have the viscosity of a 30 Weight engine oil once full operating temperature has been achieved. This ensures a high level of engine protection from the moment you turn on the ignition.
You might think that the 'W' in a motor oil's viscosity description stands for Weight, but that's just a common misconception. It actually stands for Winter. That's because 0W-30 engine oil is formulated to flow like a 0 Weight oil in cold conditions, yet offer the protection of a 30 Weight motor oil when the engine reaches its full operating temperature.
This is important, because it means that full synthetic 0W-30 oils like Castrol® EDGE® can flow quickly and easily to protect engine components right from start-up even in cold temperatures yet offer the protection of a thicker viscosity to withstand the pressure demanded by modern engines once fully warm.