Buick Excelle 1.4T uses Mobil 1 5W-30 full synthetic engine oil, while the 1.5L model uses original 5W-30 semi-synthetic engine oil. For later maintenance and oil changes, you can choose from brands such as Shell, Castrol, and 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 low temperatures down to -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 Buick Excelle 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 underneath 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 passage to drain out. Use a special wrench to remove the oil filter. Apply some new oil to the oil seal of the new oil filter and tighten it clockwise by hand. Add the new engine oil through the oil filler cap on the engine valve cover, usually filling about three-quarters of the bottle. Start the engine and let it run for 5 minutes, checking for any leaks around the oil drain plug and oil filter. If there are leaks, repairs should be made. After stopping the engine, pull out the oil dipstick to check that the engine oil level is within the standard range.
