K3 diesel oils are formulated for older, less advanced diesel engines, offering basic protection against wear, oxidation, and corrosion. They have moderate levels of additives like detergents and dispersants to help prevent sludge and carbon buildup, but are less effective in high-performance or high-temperature environments. K3 oils do not meet modern emission standards and are typically used in older trucks, agricultural equipment, and industrial machinery, where strict emissions compliance isn’t necessary. While they provide adequate protection for less demanding conditions, they may not perform well under heavy-duty or high-stress situations.