Car A/C Leaking Water?

Is there water pooling inside or outside of your vehicle?   While there are a few potential causes, the culprit may likely be an A/C water leak.  A/C water leaks are very different from the A/C refrigerant leaks that we often speak about. Read further to learn what causes car A/C water leaks and what to do when you find water where it may not belong.

Water Outside the Car

A water leak under a vehicle is a typical sight, especially on hot days after the A/C has been running. That’s because a vehicle  cabin is cooled by removing humidity from the air, and that moisture needs to be eliminated by draining outside of the vehicle.  The A/C system’s evaporator core condenses the humidity, turning it into a liquid, and eliminates it  via the evaporator drain.

In general, an exterior water drip is not something to concern yourself with.  However, if you’re worried about water leaks that are increasing in volume or frequency (or leaks that aren’t water at all), you should do further investigation or have an automotive professional perform a check up. Your vehicle runs with the help of a variety of vital fluids, any of which could leak and threaten your engine’s performance and vehicle safety.

Water Inside the Car

Water pooling inside your car, however, is a sign that something is wrong.  It’s possible the water from the A/C we just spoke about is unable to drain to the outside, in which case that blockage needs to be remedied as soon as possible.  Likely, the blockage is caused by dirt or debris which causes the A/C condensation to back up into the vehicle, much like water in a clogged sink.  If excess water remains in the evaporator core for an extended period, it can damage critical electronic A/C components.

A damaged evaporator core is another possible cause for a water leak.  It’s possible for leaves, grass clippings, etc. to reach the evaporator through the air intake vents in the evaporator core.  As the material degrades, it can become corrosive and cause the evaporator core to rust, and ultimately leak.  A leaky evaporator core may present with a tell-tale odor many automotive professionals will recognize at first whiff.

Another potential A/C issue which may cause a water leak is faulty seals.  Rubber seals can dry out and crack over time, allowing water to seep out of the system and into the vehicle.  If water is pooling under the front passenger-side floormats, this may be the issue.

Other potential causes of water inside a vehicle, however, have nothing to do with the A/C.  For example, a window, windshield or sunroof could be leaking; or there may be body damage which is allowing water to seep into the vehicle.  One easy way to discern the cause of water inside a vehicle is to check the weather.  If it’s hot and humid and the A/C has been running, that’s the likely cause of the leak.  If its wet and rainy, check your windows and body panels for                  areas which may be letting in water.

Cleaning an A/C Water Leak

Once your leaky water issue is diagnosed and repaired, make sure to thoroughly remove the water in the cabin (a wet vac is a good choice for this) and remove your floor mats to allow them to dry.  Mold and mildew thrive in humid conditions, which over time can produce a foul smell and be an impetus to a variety of health concerns for you and your passengers.

LMK 2020