What Causes Water Leakage When the Car Air Conditioner is Turned On?
4 Answers
The air conditioner drain is clogged. Solution: Turn off the power, use a Phillips screwdriver to remove the front panel and baffle, exposing the condenser and drain pan. Fill a mineral water bottle with water and flush the drain pipe along the pan, repeating several times to see if it can be unclogged. If not, use thin iron wire to slowly clear the blockage, remove the clogged material, and rinse with water until the drain flows smoothly. Finally, reassemble the baffle and panel in the reverse order of removal. Car air conditioning system: It is a device that cools, heats, ventilates, and purifies the air inside the vehicle. The car air conditioning system can control the temperature inside the cabin, heating or cooling the air to maintain a comfortable level; it can also remove moisture from the air. Dry air absorbs human sweat to create a more comfortable environment; it can intake fresh air for ventilation; and it filters the air, removing dust and pollen.
I encountered the issue of air conditioning leakage when driving my sedan, which often happens during hot summers. When the air conditioner cools, it absorbs moisture, which condenses into water and drains out through the drain hole. However, the drain hole can easily get clogged by dust, leaves, or other debris, causing water to accumulate in the evaporator box and potentially leak into the cabin, most commonly under the front passenger seat. Aging pipes or worn seals in the evaporator can also lead to water leakage. If not addressed promptly, the moisture can cause mold, unpleasant odors, and even damage electrical circuits. I recommend first trying to gently clear the drain hole with a small stick to see if you can fix it yourself. If the leakage stops, clean the debris from the drain channel before driving. If it still leaks, take it to a professional shop to check the pipes—spending a little money to replace parts can prevent bigger issues. Don’t underestimate this problem, as it can affect health, especially for families with children. Don’t let moisture cause trouble.
As someone who frequently repairs cars, nine out of ten cases of air conditioning leaks are due to drainage issues. There's a small hole at the bottom of the evaporator box responsible for draining water. If it's blocked, water will seep back in. The most common scenario is cars parked under trees, where fallen leaves cause blockages. Loose or aged pipe connections can also lead to leaks, which worsen in humid weather. Condensation buildup is normal, but backflow is not. For simple fixes, you can use an air gun to blow through the hole or buy specialized cleaning agents. Prolonged leaks can wet the carpet, making it prone to mold. During maintenance, take a moment to check these points—it won’t cost much. Daily parking away from bushes can prevent blockages, and older cars require extra attention to pipe conditions. These small details make your car more durable. Address issues promptly to avoid complications.
When I first bought my new car, I was startled by water leakage when the AC was on. Later, I learned some tips. Condensation forms during AC cooling and should drain outside, but the drain hole might be clogged or the pipe cracked. It's normal to see dripping under the car, but internal leaks need attention. Clearing the drain hole is easy—just use a thin wire to poke through. Worn seals can also cause leaks. Prevent issues by clearing it during car washes. Don’t delay; wet interiors are hard to clean. Newbies can fix this quickly. Unusual noises or odors when the AC runs are early warning signs. A full system check in spring is best.
