Why is there water dripping under the car engine?
2 Answers
If water drips from outside the vehicle (under the chassis) onto the ground, this is a normal phenomenon. Below is a detailed analysis of specific situations: 1. Principle: The car's air conditioning system is equipped with an evaporator inside the dashboard. When the air conditioning is on, the surface temperature of the evaporator is very low, causing moisture from the hot air inside the car to condense on the surface of the evaporator's heat-absorbing fins. The condensed water droplets are collected by the evaporator's plastic casing and drained out of the vehicle through pipes. If the car remains stationary for a while, you might sometimes see a puddle of very clean, transparent water. This is not a vehicle malfunction, as the engine's coolant is usually antifreeze. 2. Other dripping situations: Sometimes, the compressor located in the engine compartment (low-pressure area) can also condense moisture from the air, causing it to drip onto the ground. If the low-pressure pipes are not wrapped with thermal insulation foam, the surface of the pipes can easily condense moisture from the air, and water droplets often gather and drip from the lowest point of the pipes.
I noticed that water dripping under the engine is usually normal and may be condensation from the air conditioning system. When the air conditioning is on during summer, condensation water generated by the evaporator is discharged through dedicated drainage pipes under the chassis. This water is clear, transparent, and odorless. However, if you observe an unusually large amount of water or water with color or odor, you should be cautious. Particularly, red or green fluids are likely signs of coolant leakage, which can lead to engine overheating—a serious issue. Additionally, pay attention to the location of the leak: water dripping near the front wheels is mostly from the air conditioning, while wet spots directly under the engine require careful inspection. I recommend placing a piece of cardboard under the car before starting it in the morning and observing the water marks after driving for half an hour. This can help you preliminarily determine whether it's a sign of a malfunction.
