Issue link: http://read.dmtmag.com/i/859318
Engine Oils Background & Properties castrol.com/GPS 800 255 4417 May 2025 GPS Industry Specifications Role of Engine Oil A high quality engine oil is formulated to perform a number of roles within an engine: • Reduce frictional resistance • Protect against corrosion and wear • Assist in sealing • Contribute to cooling the engine • Facilitate the suspension of harmful combustion by-products e key to choosing an engine oil that can effectively accomplish the above tasks is to choose a fluid with good base stocks and properly blended, premium additives. Below is a quick reference of base stock characteristics and how each can influence the finished engine oil: Key Base Stock Property Engine Oil Performance Criteria Viscosity and Viscosity Index High Temp Viscosity Viscosity, Viscosity Index, Low Temp Viscosity Pour Point, and Amount of Wax Amount of Saturates Oxidation Control and Sulfur Amount of Saturates Seal Swell Control and Additive Compatibility Volatility* and Viscosity Index Oil Consumption Control In addition to meeting or exceeding industry specifications and accomplishing the duties described above, there are several desirable engine oil properties that can impact the performance of today's equipment. Typically, these properties can be enhanced when an engine oil is blended with high quality base stocks and a premium additive package using cutting-edge technology. Some oil properties and their importance are shown on the following pages. *Low volatility is especially important in engine oils because the high operating temperatures in today's diesel engines can lead to excessive oil consumption. Total Base Number or TBN Modern diesel engine oils have a characteristic referred to as alkalinity (or Reserve Alkalinity) as part of their formulation. is alkalinity — commonly called detergency, or "TBN" — describes an oil's ability to neutralize acids as they are formed in the crankcase. ese acids are a normal by-product of the combustion process when diesel fuel is burned because the fuel itself contains sulfur compounds. TBN levels in North American CK-4 engine oils typically range from 8 to as high as 11. Research suggests that TBN should not be the sole indicator for calculating drain intervals. Factors like the lubricant's viscosity, soot content, and low temperature flow are critical factors in evaluating its drain limit. A17 ecastrof