What is the fault indicated by blue exhaust from the engine?

[VonReed]

Blue smoke from the exhaust pipe indicates that the engine is experiencing an oil burning fault. The following are specific causes of oil burning: Worn valve seals: Over time, valves may wear out or age, and severe cases can affect the sealing performance of the valves, making oil burning more likely to occur. Excessive piston clearance: When a car has been used for a long time, carbon deposits from incomplete combustion may accumulate on the piston rings. If not cleaned for an extended period, this can cause the gap between the piston rings and the cylinder to expand, allowing oil to enter the combustion chamber and resulting in oil burning. In severe cases, this can even lead to engine seizure. Driving habits: Frequent rapid acceleration and prolonged high-speed driving can easily damage the lubricating oil film, leading to poor engine lubrication and wear on certain components, which may also result in oil burning. Excessive oil level: If the oil level is too high and exceeds the maximum mark, the excess oil can easily enter the combustion chamber (due to excessive internal pressure) and form gummy carbon deposits.