Can Fully Synthetic and Semi-Synthetic Engine Oils Be Mixed?

[MacRosalie]

Fully synthetic and semi-synthetic engine oils cannot be mixed. The functions of engine oil include: 1. Lubricating pistons, piston rings, and cylinders; 2. Lubricating intake valve stems; 3. Reducing engine friction and high temperatures; 4. Cleaning carbon deposits, sludge, and worn metal particles. The engine oil replacement process involves: 1. Removing the drain plug to discharge used oil; 2. Removing the oil filter; 3. Wiping the filter housing and replacing the oil filter element; 4. Adding new engine oil; 5. Checking for oil leaks. The hazards of mixing different grades of engine oil include: 1. Abnormal smoke from the exhaust pipe; 2. Accelerated sludge accumulation; 3. Reduced sealing performance of piston rods or piston rings, leading to discoloration or damage; 4. Engine malfunctions; 5. Severe wear of pistons and cylinder walls.