What Causes Excessive Water from a Car's Exhaust Pipe?
2 Answers
Water dripping from the exhaust pipe indicates that your fuel supply system is in excellent condition. Here are the three necessary conditions for water dripping from the exhaust pipe: 1. The air-fuel mixture ratio is correct. 2. The engine compression pressure is high. 3. The exhaust temperature is low. Below is detailed information about water dripping from the exhaust pipe: 1. Whether it's fuel injection or carburetor supply, the mixed air-fuel ratio is just right (indicating fuel efficiency). High engine compression pressure signifies good engine condition, with no signs of cylinder wear. 2. If the engine shows slight signs of burning oil, the cylinder pressure will decrease, leading to incomplete combustion. Incomplete combustion prevents water dripping, as the exhaust temperature won't be low. 3. A low exhaust temperature indicates correct ignition timing. The combustion gases are concentrated within the cylinder, with little or none escaping into the exhaust pipe (indicating strong engine horsepower output). For water to drip from the exhaust pipe, the engine itself must meet these conditions.
I noticed a puddle of water under my car's exhaust pipe a while ago and got quite nervous, so I rushed to ask the auto repair shop. The mechanic said it's completely normal—gasoline contains hydrogen, and when the engine burns it, water vapor is produced. In summer, it might not be as noticeable, but in winter, the exhaust pipe cools down quickly, turning that hot vapor into water droplets immediately. This happens most often when starting a cold engine, especially when idling at a red light, causing water to accumulate in the bends of the exhaust pipe. However, if there's an excessive amount of water, like a small stream, with a sweet smell or mixed with engine oil, then you should check if coolant is leaking into the cylinders—that's a serious issue. But in most cases, there's nothing to worry about; in fact, it's a sign of excellent combustion efficiency.
