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AC Leaking Water, or Is It? How to Find a Leak In Your AC System

Leak in your AC system

With summer here, many people crank up the AC when they hit the road. Once parked, you may see a small puddle on the ground, this familiar scene is your AC leaking water. But what if it’s more than a little? Here are some things that may be causing your AC to leak excessively and what you can do to find the problem on your own.

What’s Going On?Auto air conditioning

So what is that water on the ground? Any shifty used car salesman will tell you, “That’s just sweat from all the horsepower.” But more specifically, your car’s air conditioning system pulls moisture out of the air as it cools it and drains the water out before pumping the cool breeze back into the cabin. Under normal circumstances a small amount of water is OK and to be expected, especially if it’s humid out.

Dirt and Debris

While a small amount of water is fine, sometimes things can get clogged up and cause your AC system to malfunction. If you don’t notice any water when you should expect to see some, the drain may be clogged with leaves and dirt from the road. In a quiet setting and at slow speeds, you may even hear water sloshing around, which is a telltale sign of a clogged AC drain. Under the hood and below the condenser unit, you’ll spot an L-shaped rubber hose. Using a bent wire hanger, feed it into the hose to loosen any debris that may be blocking it up.

That’s Not Water

If you dip a clean rag in the puddle on the ground and notice that it either has a smell or a color, it most likely isn’t water. Your vehicle’s AC system uses both refrigerant gas (which turns to liquid when compressed) as well as oil to help cool the condenser and lubricate moving parts, respectively. In the event the drips under your car aren’t water, there are a few things you can do to find the leak:

1. Look Around. Start by visually inspecting the lines and fittings of your AC system. Since the lines are pressurized, they can form leaks after a while and will need to be repaired by your local auto shop. Take a look around the compressor as well as the other parts of the AC system to see if Freon or oil has leaked out anywhere on the components themselves.

2. Go Electronic. Your local repair shop may employ a Freon leak detector that uses a test probe. This device electronically sniffs out the presence of Freon on the outside of your vehicle’s AC components to locate a leak quickly.

3. Light It Up. Many repair shops also use a fluorescent tracing dye that can be injected into the system to find a leak. Tracing dye kits come with a pair of yellow glasses that make the dye stand out. However, if the leak is heavy enough, you may even spot it without them.

If you run your AC in the summer and spot some liquid on the ground, don’t panic just yet — an AC leaking water is a normal thing. If you find, however, that it isn’t water but possible oil from the AC system, you’ll need to investigate the problem further.

Check out all the air conditioning system parts available on NAPA Online or trust one of our 17,000 NAPA AutoCare locations for routine maintenance and repairs. For more information on finding a leak in your AC system chat with a knowledgeable expert at your local NAPA AUTO PARTS store.

Image courtesy of Flickr.


Erich Reichert View All

Erich Reichert has been an editor and on-air personality in the radio control car hobby for 12 years. A certified car nut since birth, he has written for internationally published titles such as RC Car Action, RC Driver and Xtreme RC Cars, as well as Stuff Magazine, Road and Track and Super Street. He's covered everything from product reviews and tech articles to high-profile lifestyle pieces and celebrity interviews. Erich found his passion for writing after a successful career as an art director, working with brands such as Pepsico, NASCAR, MTV, Nintendo, WWE, Cannondale Bicycles and HBO. He's also a father, an avid hockey fan and an FIA race license holder who enjoys hiking, playing drums and movies.

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