Why is there a dripping sound under the car after parking but no water?

[Eliza]

The reasons for the dripping sound under the car after parking but no water are as follows: 1. Thermal expansion and contraction sound from the exhaust pipe: Water dripping from the exhaust pipe is also a normal phenomenon, indicating good combustion efficiency of the car. The water dripping from the car's exhaust pipe is accumulated water from condensed water vapor. 2. Thermal expansion and contraction sound from components: The sound is not caused by dripping water, but rather by certain parts making noise due to thermal expansion and contraction or returning to position after movement. Components like the catalytic converter, exhaust pipe, and turbocharger can all produce similar sounds. The specific principle is that after gasoline burns, it forms water and carbon dioxide. When the ambient temperature is high, it remains as water vapor, which is expelled before condensing; when the ambient temperature is low, the water vapor condenses into water droplets on the exhaust pipe wall, thus forming water.