What are the causes of engine oil burning?

[DelElliana]

Engine oil burning is caused by: 1. External oil leakage; 2. Failure of front and rear oil seals; 3. Wear or failure of main bearings; 4. Wear or damage to connecting rod bearings; 5. Wear or damage to camshaft bearings; 6. Cylinder liners becoming tapered or out of round; 7. Wear of valve stems or guides. The functions of engine oil are: 1. Lubrication to reduce wear - between the piston and cylinder of the engine, relative sliding of the crankshaft and bearing shells causes wear. Engine oil forms a thick oil film between the two sliding surfaces, separating the relatively sliding parts to reduce wear; 2. Cooling - engine oil carries heat back to the oil tank and dissipates it into the air, helping the radiator cool the engine; 3. Cleaning - engine oil circulates carbon deposits, sludge, and worn metal particles from engine components back to the oil tank, flushing away dirt generated on the parts through the flow of the lubricating oil.