Buick Excelle 1.4T originally uses Mobil 1 5W-30 full synthetic oil, while the 1.5L version uses OEM 5W-30 semi-synthetic oil. For later maintenance oil changes, you can choose brands such as Mobil, Shell, Castrol, or Total. The viscosity of engine oil changes with temperature, so special attention should be paid 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 temperatures as low as -30°C. The smaller this number, the better the low-temperature fluidity, resulting in smoother cold starts for the vehicle. The latter 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 providing better lubrication performance under high-temperature conditions. The method for changing the engine oil in a Buick Excelle is as follows: Wait for the engine temperature to cool down, allowing the oil to drain back into the oil pan; Use a wrench to loosen the oil drain plug and place an oil pan underneath to catch the old oil until it stops flowing. Start the engine for about 30 seconds to allow the oil in the main oil gallery to drain out; Use a special wrench to remove the oil filter; Apply oil to the gasket of the new oil filter and tighten it clockwise by hand; Add new oil through the oil filler cap on the engine valve cover, typically filling about three-quarters of a standard oil container; Start the engine and let it run for 5 minutes, then check for any leaks around the oil drain plug and oil filter. If leaks are found, repairs should be made; After stopping the engine, pull out the dipstick to check that the oil level is within the standard range.
