High-viscosity engine oil is not always better; its applicability needs to be comprehensively judged based on the vehicle model, driving conditions, and climate factors. High-viscosity engine oils (such as 5W-40 or 10W-40) can form a thicker oil film under high-temperature or high-load operating conditions, enhancing sealing performance and anti-wear ability, making them suitable for high-performance vehicles or vehicles that frequently operate at high speeds. For instance, while Petronas 5W-40 excels in high-temperature protection, its use in precision-designed modern engines (such as most Japanese vehicles) may impair fuel efficiency due to excessive viscosity. Conversely, low-viscosity engine oils (such as 0W-20 or 5W-30) provide faster component lubrication and reduced fuel consumption, making them more suitable for daily commuting or moderate driving. When selecting engine oil, priority should be given to the viscosity grade recommended in the vehicle manual, with consideration for climate conditions (e.g., in tropical regions, oils with higher high-temperature viscosity may be preferable). Products like the Petronas Syntium series offer multiple viscosity options, balancing cleanliness and anti-wear properties, but the core principle remains "matching requirements" rather than blindly pursuing high viscosity.
