What Causes White Smoke?
2 Answers
Common causes: Engine temperature too low: Some diesel fuel does not burn and turns into oil vapor, which is discharged from the exhaust pipe along with the exhaust gas. Water in the fuel system: There is water in the fuel or combustion chamber, which is heated into steam by the heat released during combustion in the cylinder and discharged from the exhaust pipe. Injection timing too late: Due to late injection timing, the cylinder temperature has already dropped when fuel is injected, causing some diesel fuel to turn into oil vapor without burning. Poor fuel injector atomization: Poor atomization leads to incomplete combustion of diesel fuel, which mixes with high-temperature exhaust gas from normally operating cylinders in the exhaust pipe. Low cylinder pressure: Some diesel fuel turns into oil vapor without burning and is discharged from the exhaust pipe.
Last time I saw white smoke puffing out of the exhaust pipe like a boiling kettle, it scared me to death! Later I realized it was because of the cold winter. When hot air from the engine meets cold air, it condenses into water vapor, looking like thick white smoke, which disappears after driving for a while as the engine warms up. However, if white smoke keeps coming out, especially with a sweet smell, it's most likely coolant leaking into the engine. Common causes include a blown head gasket or a cracked engine block. This needs immediate repair, otherwise the problem will worsen with continued driving. My neighbor's car had this issue last time and ended up costing thousands to replace the engine.
