05wt

05wt refers to a specific designation within the SAE (Society of Automotive Engineers) viscosity grading system for engine oils. The "05" in this designation represents the oil's viscosity at low temperatures, specifically its cold-cranking viscosity. A lower number indicates a thinner oil at cold temperatures, which allows for easier engine starting and better oil flow during cold weather. The "wt" part of the designation, while not a standard part of the SAE grading, often appears in specific product names or internal company codes to denote a particular viscosity grade, likely emphasizing its "winter" (cold weather) performance.

SAE 0W-20 is a common example of a low-viscosity oil that would fall under this type of designation. Oils with a "0W" rating are designed to perform exceptionally well in very cold climates, providing superior protection during cold starts by flowing more readily than thicker oils. This can lead to reduced engine wear and improved fuel efficiency when the engine is cold. The subsequent number in a full viscosity grade, such as the "20" in 0W-20, indicates the oil's viscosity at operating temperature. Therefore, 05wt likely signifies an oil intended for cold-weather applications with a specific low-temperature viscosity characteristic.