Should the CS75 use 5W30 or 5W40 engine oil?

[SerenityAnn]

The CS75 should use 5W30 engine oil. It is recommended to use the original SL-grade 5W30 engine oil. 5W30 has better fluidity than 5W40, which helps reduce fuel consumption and dissipate heat from the engine more quickly. The "W" stands for winter, and the smaller the number before it, the better the oil's low-temperature fluidity, indicating a lower usable environmental temperature and better engine protection during cold starts. For example, 5W40 can be used in environments with temperatures below 40 degrees, while 5W30 can be used in environments with temperatures below 30 degrees. The difference between 5W30 and 5W40 engine oil is that higher viscosity oil leads to higher fuel consumption and louder engine noise, but it provides better sealing performance. Therefore, the choice of oil viscosity should also consider the age of the vehicle. Newer engines with tight component clearances should use lower viscosity oil, while vehicles with significant engine wear should use higher viscosity oil. Precautions for using engine oil: Choose oil based on the engine's requirements, ensuring it matches the engine. Multi-grade oil is recommended due to its advantages in fuel efficiency, long service life, and high efficiency, providing better protection for the engine.

[LaylaDella]

My CS75 has been using 5W30 engine oil for over three years without any issues. The manufacturer's manual clearly recommends 5W30, mainly because this type of oil has good low-temperature fluidity, reducing engine wear during cold starts in winter. Additionally, 5W30 has slightly lower viscosity, which theoretically can save some fuel. However, last month during a self-drive trip to Northeast China, a local repair shop suggested I temporarily switch to 5W40, saying it offers better high-temperature protection at minus thirty degrees Celsius. After returning, I switched back to 5W30 since it's unnecessary to use oil with too high viscosity for driving in southern cities. Besides temperature, choosing engine oil also depends on the vehicle's condition—5W30 is sufficient for new cars, but if the engine has minor wear after running over 100,000 kilometers, the oil film of 5W40 might provide better protection for metal components.

[LaLandon]

As a CS75 owner who frequently drives to construction sites, I've repeatedly tested two types of engine oil. When using 5W30, the fuel consumption is indeed lower, saving about half a liter per 100 kilometers. However, after prolonged heavy loads or highway driving, the engine noise becomes noticeably louder. Later, I switched to 5W40, and the power feels more stable when climbing hills with a full load, especially during continuous driving for three to four hours on high-temperature roads in summer. The oil temperature gauge shows about 5 degrees more stability compared to using 30. But for daily commuting, 40 is a bit overkill—it puts slightly more load on the oil pump and consumes more fuel. Now, I use 30 in spring and autumn and 40 in summer, making sure to clean the oil circuit when switching. Additionally, turbocharged models require extra attention to high-temperature protection.

[ReedFitz]

I've worked at a Changan 4S store for many years, and most CS75 models we handle use 5W30 factory oil. This viscosity strikes a balance between lubrication and fuel economy, with the manufacturer conducting tens of thousands of kilometers of testing verification. Unless you live in areas like Turpan, Xinjiang where summer ground temperatures reach 60°C, or frequently drive fully loaded on mountain roads, there's no need to upgrade to 40 viscosity. A common misconception is that higher viscosity provides better engine protection. In reality, modern engines have high precision, and 5W30 oil film is completely sufficient - using 40 viscosity actually increases crankshaft resistance. Regular maintenance is more important than obsessing over viscosity; full synthetic oil should be changed every eight thousand kilometers.