
The original engine oil used for the BYD S7 is of the 5W-40 type. In terms of compatibility, the original oil is more suitable for the engine. However, depending on different needs, engine oils can offer other benefits such as noise reduction, fuel efficiency, and enhanced performance. Therefore, you can also choose engine oils from brands like Mobil, Shell, and Castrol. The viscosity of engine oil changes with temperature, so it's important to pay special attention to its performance under both low and high temperatures. For example, in 5W-30, the first number indicates low-temperature fluidity. 5W means it can withstand low temperatures down to -30°C. The smaller this number, the better the low-temperature fluidity, making cold starts smoother. The second number represents the oil's kinematic viscosity at 100°C. A higher number means the oil can maintain its viscosity index better at high temperatures, which can also be understood as providing better lubrication performance under high-temperature conditions. The method for changing the engine oil in a BYD S7 is as follows: Wait for the engine temperature to drop, allowing the oil to flow back into the oil pan. Use a wrench to loosen the oil drain plug and place an oil pan to catch the old oil until it stops flowing. Start the engine and let it run for 30 seconds to allow the oil in the main oil passages to drain out. Use a specialized wrench to remove the oil filter. Apply oil to the oil seal of the new oil filter and tighten it clockwise by hand. Add the new oil through the oil filler cap on the engine's valve cover, typically filling up to three-quarters of the oil container. Start the engine and let it run for 5 minutes, checking for any leaks around the oil drain plug and oil filter. If leaks are found, perform necessary repairs. After stopping the engine, pull out the oil dipstick to ensure the oil level is within the standard range.

My BYD S7 is the 1.5T turbocharged version. I previously checked the user manual specifically, which clearly states that 5W-40 synthetic oil should be used, with the viscosity number 40 being particularly important. During the last maintenance at the 4S店, I saw the mechanic also adding 5W-40 to a 2.0T car, saying this grade is suitable all year round—it ensures smooth starts in winter sub-zero temperatures and provides adequate high-temperature protection in summer. Remember to choose SP-grade oil for better anti-wear performance, with an oil change interval recommended at around 8,000 km. For aggressive driving, changing it earlier at 7,000 km is safer. Never skimp and use other viscosity oils, especially those starting with 10W, as insufficient protection for the turbocharger may lead to oil burning issues, which would be counterproductive.

Last winter when I changed the oil for my BYD S7, I did some research. Actually, choosing engine oil mainly depends on two indicators: the SAE grade 5W-40 is most suitable. The number 5 before the letter W represents low-temperature fluidity, while the 40 after it indicates high-temperature viscosity. For cold northern regions, 5W is recommended, while for particularly hot southern cities, 10W-40 is also acceptable. The oil specification should be SL grade or above, with SN or SP grade full synthetic being the mainstream choice nowadays. If you're doing it yourself, the quantity needed is approximately 4.5 liters. Remember to check the dipstick level after adding. I recommend trying Castrol Magnetec or Mobil 1, as their anti-wear additive formulas are more suitable for the S7's turbocharged engine, reducing cold start wear and extending engine life.

For BYD S7 engine oil selection, just remember two key points: The viscosity must be 5W-40, and the API grade should be at least SL or higher. When getting maintenance at the repair shop, remind the mechanic to use full synthetic oil to avoid being tricked into using semi-synthetic. Turbocharged engines have higher demands on oil quality, and full synthetic offers better thermal stability, especially during frequent start-stop situations in traffic jams. I always supervise the entire oil change process to ensure complete drainage of old oil before adding new oil, with a quantity between 4.3-4.7 liters. Additionally, check the oil level yourself every three months to ensure it stays at the midpoint between the markers.


