5W30 is a viscosity grade identifier for engine oil, classified under the SAE international standard. The "W" stands for Winter, and the preceding number "5" indicates the oil's fluidity in low-temperature environments-specifically, its ability to maintain good flow performance at minus 30 degrees Celsius. The following "30" denotes the oil's kinematic viscosity at 100°C; a higher value indicates more stable oil film integrity under high-temperature conditions, effectively reducing engine wear. This multi-grade oil combines low-temperature startup performance with high-temperature protection, serving as an all-season option particularly suited for regions with significant temperature variations. Oil viscosity selection must strictly adhere to the vehicle manufacturer's maintenance manual recommendations, as improper use may result in inadequate lubrication or increased fuel consumption. Currently, mainstream engine oils are categorized into mineral oil (approximately RM80-RM120 per 4L), semi-synthetic oil (RM120-RM180 per 4L), and fully synthetic oil (RM180-RM300 per 4L). Notably, Japanese and Korean vehicle models, owing to their precision-engineered designs, typically specify 5W30 viscosity, whereas German vehicles often require higher-viscosity 5W40 oil. Regular oil and filter changes (recommended every 5,000-10,000 kilometres) are essential for prolonging engine service life.
