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.

[VanGenesis]

When dealing with engine failures, I often find that the core issue of oil burning is mechanical part aging. After the piston rings wear out, oil seeps into the combustion chamber through the ring gaps and burns, especially in high-mileage engines. Valve stem seals can also age and deform, causing oil to leak in from the stem side; if the turbocharger's oil seal cracks, lubricant directly enters the intake pipe and burns. Additionally, poor sealing of the oil pan gasket or crankcase cover can indirectly cause oil burning. These situations not only accelerate component wear but also cause blue smoke from the exhaust pipe. Long-term neglect may lead to engine overheating or more severe damage. It is recommended to immediately use professional instruments to check internal pressure differences once abnormal oil consumption is detected and replace parts based on the diagnosis.

[AutumnLee]

After years of driving experience, I've concluded that the causes of oil burning are often related to inadequate daily maintenance. For example, piston rings can accumulate carbon deposits and wear out due to prolonged use without oil changes or the use of low-quality oil, allowing engine oil to seep into the cylinders. The rubber seals on the valve stems can also age and crack over time, leading to oil leaks and burning. Additionally, excessive engine sludge can clog the oil ring holes, accelerating oil consumption. If not repaired in time, not only will blue smoke frequently appear, but it may also shorten the engine's lifespan or even cause a breakdown on the road. I remember trying oil additives before replacing the seals, but the effect was temporary, and ultimately, a disassembly and inspection were necessary. The key to avoiding such issues is regular oil changes and carbon cleaning, especially after long-distance driving.

[VonJosiah]

I usually focus on fuel efficiency and environmental protection. Oil burning commonly occurs due to seal system failure or unstable oil pressure. Piston ring wear is the most prevalent cause, where oil directly enters the combustion chamber and burns; fatigued or damaged valve stem seals can also lead to similar leaks. Poor vehicle design, such as suboptimal oil passage structures or inadequate lubrication, can exacerbate the issue. Symptoms include blue exhaust smoke and rapid oil consumption, and ignoring these can worsen pollution emissions. Regular oil level monitoring and timely replacement of worn parts are recommended for prevention.