What Causes Excessive Water from Car Air Conditioning?
3 Answers
Excessive water from car air conditioning is primarily caused by high environmental humidity. When the car air conditioning cools the hot air inside the cabin during summer, the high humidity in the air leads to a significant amount of water vapor. This water vapor condenses into liquid water on the evaporator as it releases heat during the cooling process. The air conditioning system collects this water and drains it out of the vehicle through a drainage pipe. If the environmental humidity is high, the amount of condensed water on the evaporator will increase accordingly. The car air conditioning system is the most critical component of the vehicle's climate control, providing services such as cooling, heating, ventilation, and air purification. Nowadays, the air conditioning system has become one of the benchmarks for evaluating a car's quality. Using the air conditioning helps promptly remove moisture from the cabin air, creating a more comfortable environment. By utilizing the car air conditioning system, passengers can enjoy a comfortable riding experience, reducing driver fatigue and enhancing driving safety. Water vapor from the external air will liquefy and condense on the pipes and casing of the air conditioning system at such low temperatures. If not properly drained, it can lead to dampness around the air conditioning system (inside the dashboard) and corrosion of components.
I've been driving for over twenty years and often encounter the issue of excessive air conditioning water. This is quite common during hot weather or high humidity seasons, especially in places like Guangdong where high temperatures bring more moisture in the air. When the AC cools the air, the evaporator causes water vapor to condense into droplets, which then drain under the car. So, seeing a puddle of water after parking is normal. However, if the amount of water is unusually large—like a big pool every time you park—or if you notice water stains on the car's floor mats, something might be wrong. Most likely, the drain tube is clogged with dust or small insects, blocking the small pipe and causing water to backflow into the car. I once had this issue where water soaked the floor mats, but I fixed it by using a thin wire to clear the debris from the drain outlet. Ignoring this can lead to mold growth, damage to electrical components, and even health issues. I recommend checking the drain tube during regular maintenance—it's usually located under the engine bay—it's not too much trouble.
I noticed a significant amount of water draining from my car's AC shortly after purchasing it, especially during the rainy season when I could constantly hear water dripping underneath the car. In fact, the working principle of an air conditioner is to cool the air, causing moisture to condense into water droplets that are then drained out through a small tube. It's normal for there to be more water droplets during humid summers. However, if the amount of water suddenly becomes excessive or starts leaking into the cabin and dripping onto the seats, it might indicate a problem with the drainage system. The most common issue is a clogged tube, where leaves or mud block the outlet, preventing water from draining and causing it to overflow into the car's interior. I once saw a mechanic demonstrate this, explaining that it can easily damage the AC's internal components or cause corrosion, so any abnormalities should be addressed promptly. To check it yourself, you can glance at the amount of water on the ground after parking. If it's unusually large, seek professional help to unclog it. Additionally, frequent use of the AC will increase the drainage volume, but don't worry too much as long as there's no blockage—it's not a major issue.
