What causes blue smoke during cold engine start?

[BradleyDella]

Blue smoke during cold engine start indicates that the vehicle is burning engine oil. The symptoms include: accumulation of black, wet oil sludge in the exhaust pipe, accompanied by particulate matter, and a noticeable smell of engine oil. Blue smoke during cold start confirms that after the engine is turned off, engine oil enters the combustion chamber. When the engine is started again, the oil in the cylinder burns together with the air-fuel mixture under high temperature, producing blue smoke. The reasons for blue smoke during cold engine start include: 1. Poor sealing between the valve guide and the guide bore, causing oil leakage into the combustion chamber; 2. Failure to perform maintenance as required; 3. Long-term incorrect driving habits, prolonged operation with insufficient engine oil, or continuous overloading, leading to premature engine aging and wear.