Why is there excessive white smoke coming from the exhaust pipe?
2 Answers
Here are the reasons for white smoke from the exhaust pipe: 1. In winter, the main products of complete gasoline combustion are carbon dioxide and water, along with a small amount of pollutants. Water originally exists in the form of water vapor. When the engine is just started, the exhaust pipe and the air inside it are cold. The water vapor expelled from the cylinders quickly condenses into water mist upon encountering the cold exhaust pipe and air. This water mist is expelled as the white smoke we see. This is a normal phenomenon. 2. Water entering the cylinders turns into a large amount of water vapor, creating excessive white smoke. The most common cause is a damaged cylinder head gasket. The engine block and cylinder head have water passages that run through them, so they must be tightly sealed to prevent water from leaking. 3. Excessive water content in the gasoline. Similar to coolant entering the cylinders, the fuel injector sprays not pure gasoline but a mixture that includes some water. Water cannot burn and turns into a large amount of water vapor when heated, which is expelled from the vehicle as excessive white smoke.
Recently, my car's exhaust pipe was emitting thick white smoke. At first, I thought it was normal in winter. But then I noticed the coolant was depleting unusually fast, and there was a sweet smell, so I rushed to the repair shop. The mechanic checked and said the cylinder head gasket was damaged, allowing coolant to leak into the combustion chamber, where it was burned and expelled as water vapor. The technician mentioned that prolonged engine overheating or an aging cooling system can easily cause this issue. Fortunately, it was caught early; otherwise, engine seizure could have been a serious problem. I recommend everyone to regularly monitor the temperature gauge and coolant level. If you notice persistent white smoke, don't ignore it—get it checked promptly.
