Why Does the Engine Burn Oil?
2 Answers
The main reasons why an engine burns oil are excessive piston clearance, abnormal operation of the valve oil seals, and driving habits. Below are the causes of oil burning: 1. The phenomenon of engine oil burning occurs when oil enters the engine's combustion chamber and participates in the combustion of the air-fuel mixture. After the engine burns oil, the car's exhaust pipe emits blue smoke, which is a relatively common occurrence. 2. Over prolonged use, cars inevitably develop carbon deposits, which can accumulate on the piston rings. If not cleaned for a long time, these deposits can widen the gap between the piston rings and the cylinder wall, allowing oil to flow into the combustion chamber. The oil then participates in combustion, and in severe cases, it can even lead to engine knocking. Therefore, regular carbon cleaning is crucial and can be considered a preventive measure against oil burning.
As a seasoned driver with twenty years of experience, I've seen too many cases of oil burning. There are several common reasons for engine oil burning: the most common is worn or aged piston rings, especially in high-mileage older cars. Over time, the sealing of piston rings deteriorates, allowing oil to seep into the combustion chamber. Secondly, aging valve stem seals are also an issue—rubber components harden and crack under prolonged high temperatures, causing oil to leak down the valve stem and burn. Additionally, in turbocharged models, worn turbo bearings can allow oil to enter the intake tract through bearing gaps. Poor maintenance leading to excessive carbon buildup can also worsen oil consumption. Less commonly, oil pan gasket or crankshaft seal leaks may occur. If you encounter this issue, don't rush into an engine overhaul—first check the rate of oil level drop before deciding how to proceed.
