Regular car engine oil typically refers to mineral oil or semi-synthetic oil suitable for daily driving needs, primarily fulfilling basic engine protection and lubrication requirements. Mineral oil, an economical option refined from crude oil, costs approximately RM50-RM100 per 4L. It is suitable for low-emission microcars or naturally aspirated engines, with a recommended replacement interval of every 5,000 kilometres or 6 months. Semi-synthetic oil (e.g., 10W-40 or 5W-30 viscosity grades) blends mineral oil with synthetic base oil, priced around RM120-RM180 per 4L. It offers superior oxidation resistance and is suitable for regular family cars, allowing an extended replacement interval of up to 7,500 kilometres. While fully synthetic oil (such as 5W-40) delivers enhanced performance (including high-temperature resistance and extended protection), its higher cost (RM200-RM300 per 4L) makes it predominantly used in turbocharged or high-performance vehicles. For instance, older models may use 15W-40 mineral oil, whereas newer naturally aspirated engines are better suited for 5W-30 semi-synthetic oil. Regular oil changes are more critical than merely pursuing higher-grade oils, as substandard oil may cause sludge buildup or engine wear.
