What Causes Water Leakage from the Car Air Conditioner?

3 Answers
LeTimothy
07/25/25 6:14am
Water leakage from the car air conditioner can occur due to the following reasons: 1. Improper installation of the unit: The indoor unit is tilted, or the pipe opening direction is too high. 2. Poor drainage pipe: The drainage pipe is loose or bent into a wave shape, causing poor drainage. 3. Condensation on the pipes: The insulation material on the pipes is of poor quality or too thin, leading to condensation when refrigerant passes through. 4. Dripping from the heat exchanger: Dust accumulation on the heat exchanger causes uneven temperature distribution, resulting in water droplets forming midway on the heat exchanger and dripping outside the drain pan; insufficient refrigerant in the air conditioning system can cause the indoor unit to freeze, and the melted ice forms water droplets that do not directly fall into the drain pan.
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AndresMarie
08/11/25 1:01pm
I've encountered the issue of car air conditioning leaking several times, making the car floor all wet, which is really annoying. The main reason is the condensation water produced when the air conditioning is cooling. Normally, it should be drained out through the drain pipe, but that pipe can easily get clogged by dust or leaves, causing the water to seep into the car when it has nowhere to go. Another issue is the accumulation of dirt in the evaporator box, which can block the drain outlet and also lead to leaks. What's more troublesome is if the pipe is cracked due to aging or wasn't sealed properly during installation, the leakage can be even worse. I suggest first checking if the floor mats are wet. If you find a leak, try using a thin wire to clear the drain outlet in the engine compartment—you can tell if it's blocked or not. If it's blocked, get it fixed immediately; otherwise, the accumulated water can cause mold, damage the seats and electrical circuits, and even affect driving safety in the long run. Regularly cleaning the air conditioning filter can help prevent this problem.
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MacAnna
09/27/25 5:17am
Most cases of car air conditioner leaks are caused by the inability to drain condensation water. When the AC is running, water droplets condense as the air cools down. This water is supposed to flow into a drain tube and exit the vehicle, but that tube often gets clogged with dirt or debris, forcing the water to flow back into the cabin. Other common causes include a cracked drain tube or an improperly sealed evaporator case. From my experience handling many such cases, the simplest solution is to check under the car for blockages in the chassis drain outlet—if you hear dripping sounds, there might be a leak. Don't delay repairs, as the leaked water can corrode carpeting, cause mold growth, and make breathing uncomfortable while driving. If cleaning the drain outlet doesn’t help, it’s best to have a technician inspect it to avoid damaging electrical modules. Remember to regularly clean the drainage system during maintenance.
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