Changan CS55 uses original equipment manufacturer (OEM) oil produced by Great Wall with specifications of 5W40 full synthetic oil or 0W40 full synthetic oil. For later maintenance and oil changes, you can choose Shell HX7-5W-40 synthetic oil, OEM Castrol Magnetec 5W-30, or Mobil full synthetic oil. According to the official maintenance manual, it is recommended to use 5W-40 full synthetic oil. The viscosity of engine oil changes with temperature, so special attention should be paid to its performance under low and high temperatures. For example, in 5W-30, the first number indicates low-temperature fluidity, where 5W means it can withstand temperatures as low as -30°C. The smaller this number, the better the low-temperature fluidity, resulting in smoother cold starts for the car. The second number represents the kinematic viscosity of the oil at 100°C. A higher value means the oil can maintain its viscosity index better at high temperatures, which can also be understood as better lubrication performance under high-temperature conditions. The method for changing the engine oil in a Changan CS55 is as follows: Wait for the engine temperature to drop and allow 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 for 30 seconds to allow the oil in the main oil passage to drain; Use a special wrench to remove the oil filter; Apply oil to the oil seal of the new oil filter and tighten it clockwise by hand; Add new oil through the engine valve cover filler port, usually filling about three-quarters of the oil container; Start the engine and let it run for 5 minutes, then check for any oil leaks around the drain plug and oil filter. If there are leaks, perform necessary repairs; After stopping the engine, pull out the oil dipstick and check that the engine oil level is within the standard range.
