Why do Japanese cars require low-viscosity engine oil?
3 Answers
The reason Japanese cars require low-viscosity engine oil is: The more precise the components, the less dependent they are on the viscosity of the engine oil. The functions of engine oil include: lubrication and wear reduction, auxiliary cooling, sealing and leak prevention, rust and corrosion prevention, and shock absorption. Engine oil is categorized into mineral oil, semi-synthetic oil, and fully synthetic oil. The method for changing engine oil is: 1. Lift the car, remove the undercover, and place a container of about 10 liters under the oil drain plug; 2. Unscrew the oil drain plug, use an air gun to blow for two minutes at the oil filler port, then tighten the oil drain plug after draining and wipe it with a tissue to check for leaks; 3. Reinstall the undercover and lower the car, then use a funnel to add engine oil through the oil filler port.
I usually enjoy keeping up with automotive knowledge and have noticed that Japanese cars generally recommend low-viscosity engine oil. This is mainly because their engines are designed with precision, featuring smaller gaps between components. Using high-viscosity oil can lead to less smooth lubrication, increased friction, and higher fuel consumption as the engine works harder. During cold starts in winter, low-viscosity oil flows more quickly, providing faster engine protection, reducing wear, and improving startup efficiency. Additionally, with the current emphasis on fuel efficiency and environmental protection, low-viscosity oil helps reduce engine resistance, allowing you to travel a few more kilometers per tank, saving money and being eco-friendly. From some forums, I’ve also learned that Japanese automakers have confirmed through testing that low-viscosity oil extends engine life, making it suitable for urban driving conditions with frequent starts and stops.
In my work, I frequently encounter Japanese car maintenance cases where owners opt for high-viscosity oil for convenience, only to experience increased engine noise and soaring fuel consumption. Japanese engines feature compact internal spaces with smaller clearances. Low-viscosity oil flows like a fine stream, ensuring more uniform lubrication that reduces component friction and wear. It also enables faster cold starts, minimizing hard-start damage. This aligns perfectly with manufacturers' optimized designs, delivering long-term maintenance savings. I've also observed that low-viscosity oil has appropriate change intervals at reasonable costs, preventing premature engine aging. Just remember to check oil levels diligently during maintenance.
