How to Tell If Your Car Air Conditioning Has a Leak (2023)

Can’t handle the heat from your malfunctioning car A/C? If you’ve noticed your vehicle's air conditioning is losing its cool, a leak might be to blame. However, unlike motor oil leaks, car A/C leaks aren’t always easy to spot. Look out for these symptoms that might clue you into a car air conditioning leak.

What is a car A/C leak?

Your car’s A/C is a system that cools the air and regulates humidity inside the cabin. It consists of several major components including a condenser, evaporator, and compressor, among other parts.

To keep your cabin cool and conditioned, a colorless (and relatively odorless) refrigerant circulates through the A/C system. As refrigerant travels through your A/C system, it cycles through liquid and gas states, which effectively allow it to “suck” heat out of the evaporator in the cabin, push it out of the condenser under the hood, and then fan cooler air through the evaporator and into the vehicle. Whew.

Refrigerant can leak at any point in this cycle, especially when parts of the system become loose, worn, or damaged. Since A/C refrigerant is a gas at certain stages of the cooling cycle, a tiny crack or unnoticeable hole somewhere can allow it to escape — making it extra hard for you to notice leaks until you spot symptoms of them.

How do I spot a car A/C leak?

1. Your car A/C is blowing warm air.

If you feel like your car A/C is blowing 80°F even though the temperature setting on the dash is at its lowest point, you might be losing refrigerant. However, leaks aren’t the only reasons why your car may be blowing hot air, so it’s best to get an A/C performance check to figure out the root cause of your A/C issues.

2. You hear a clicking sound when your A/C is running.

If you notice a clicking noise while your car A/C is running, your compressor might be short cycling. Some drivers compare this sound to a loud switch turning on and off continuously. In many cases, it is especially noticeable if one is standing outside of a car with the A/C running.

A short cycling car A/C compressor can be caused by a number of factors, including but not limited to low refrigerant levels resulting from a leak! As with other annoying car A/C problems, the driver's smartest option is to seek professional diagnostics over DIY solutions.

3. Your dashboard alerts you to issues.

Although not all cars have a dedicated alert light for air conditioning issues, yours might! In certain vehicle models, a car A/C malfunction like a leak may trigger the check engine light. In others, a dash light may not be triggered at all! The best way to know whether or not car A/C problems will trigger dash lights or warnings is by checking the warning light and indicator section of your owner’s manual.

Why are car A/C leaks hard to see?

Unlike motor oil and brake fluid, car A/C refrigerant is a colorless and relatively odorless substance that cycles through gas and liquid states. Because of its unique properties, A/C refrigerant rarely leaves a visible trail, streak, or odor behind when it leaks, which is why it’s hard for the untrained eye to spot.

When dealing with potential A/C leaks, the professionals at Tires Plus use advanced solutions to trace the source. In some cases, technicians use UV leak detection — adding a bit of UV dye to the car A/C system and cycling it through. When the dye circulates through the system, it escapes through any leak sites, which are then identified using a specialized flashlight.

In other cases, technicians use an electronic “sniffer” tool, which works similarly to a metal detector, except it’s designed to pick up traces of refrigerant. When the sniffer detects high concentrations of refrigerant, it alerts the technician with a series of high-pitched beeps, helping them track down the location of the leak.

Don’t sweat it!

If you’re breaking a sweat over a warm or weak car A/C, don’t! Drive to your local Tires Plus for professional diagnostics, car air conditioning repairs, or a yearly A/C Performance Check to help your car keep its cool.


What is the easiest way to find the leak in car conditioner? ›

How to Find AC Leaks in Your Car (UV Dye) - YouTube

What 3 methods can be used to find a leak in the AC system? ›

soap bubble method; fluorescent dye method; or. electronic leak detection method.

How do you test for an AC system leak? ›

An AC leak test with nitrogen—the preferred test by Homesense technicians—adds a greater degree of clarity to leak detection, though for slightly more cost. With this nitrogen leak test procedure, the HVAC technician first removes any remaining freon or Puron and pumps compressed nitrogen into the refrigeration system.

How do I find an AC leak in my car without dye? ›

How To Quickly Find Car AC Leaks - YouTube

How do I know if my car AC is leaking refrigerant? ›

5 signs of an AC refrigerant leak
  1. Loss of cooling power.
  2. Registers not blowing cool air.
  3. Hissing sounds coming from your indoor unit.
  4. Coils are frozen.
  5. An AC refrigerant leak equals elevated electric bills.
Sep 12, 2017

What is the best leak detection method? ›

After determining the general area of a leak with the use of an electronic detector, soap bubbles is a great method of pinpointing the exact location of the leak.

What is the most common source of refrigerant leaks? ›

Refrigerant leaks occur due to poor installation of some aspects of your HVAC unit. For instance, the most common cause of a leak is due to overtightening the flare connections.

Where do most Freon leaks occur? ›

Freon leaks are typically found at the schrader valve, valve cores, evaporator coil, copper lines, “U” connectors, weld joints, electrical connection to the compressor body, or the copper tubing. Most of the time, the leak will usually occur in the evaporator coil.

Does Stop leak work for car AC? ›

These type of stop leaks rarely work due to the high pressure in your air conditioning system. The second type of stop leak is much safer to use as it is a chemical sealing agent. These chemical stop leaks are safer to use as they don't clog other parts of your air conditioning system.

What is the best AC leak sealer for cars? ›

Top 10 Best Ac Stop Leak Reviews & Comparison
1InterDynamics Car Air Conditioner Refrigerant Stop Leak Kit, Certified A/C Pro Leak Stop Kit for...
2Red Angel A/C Stop Leak & Conditioner
3INTERDYNAMICS-QUEST R134a Leak Detector - Sealer - 3 OZ
4BlueDevil Products Red Angel A/C Stop Leak
6 more rows

How much does it cost to fix an AC leak in a car? ›

The cost to fix a car's AC leak could cost $100 to $800, depending on the reason for the issue. If your car's AC system is leaking, it's often because you have a cracked hose that needs replacing. Other culprits could require additional replacements of your sensors, the compressor, or the condenser.

How do I find a vacuum leak in my car AC? ›

You can and should pull a vacuum, look at the reading on the manifold gauge set, let it sit for some amount of time (overnight is best), and see if the vacuum reading drops, because if it does, there's a leak somewhere. But the vacuum itself is really almost no help in finding the leak.

What is the best Freon leak detector? ›

Best Refrigerant Leak Detectors
Refrigerant Leak DetectorsSensitivityWarranty
Inficon Refrigerant Leak Detector0.25 oz/year2 years
Aprvito Refrigerant Leak Detector0.11 oz/year1 year
Elitech Refrigerant Leak Detector0.14 oz/year3 years
Yosoo Refrigerant Freon Detector0.18 oz/year1 year
1 more row
Jan 31, 2022

How much does it cost to fix an AC leak in a car? ›

The cost to fix a car's AC leak could cost $100 to $800, depending on the reason for the issue. If your car's AC system is leaking, it's often because you have a cracked hose that needs replacing. Other culprits could require additional replacements of your sensors, the compressor, or the condenser.

How do you fix a leaking air conditioner? ›

Depending on the location and severity of the damage, your HVAC technician will perform one of two common repairs. Patch the cracked coil. If the hole isn't too large, your technician will repair the hole using a patch designed to hold up to the refrigerant liquid and reduce the risk of further leaks. Coil replacement.

Top Articles
Latest Posts
Article information

Author: Gov. Deandrea McKenzie

Last Updated: 23/10/2023

Views: 5834

Rating: 4.6 / 5 (46 voted)

Reviews: 85% of readers found this page helpful

Author information

Name: Gov. Deandrea McKenzie

Birthday: 2001-01-17

Address: Suite 769 2454 Marsha Coves, Debbieton, MS 95002

Phone: +813077629322

Job: Real-Estate Executive

Hobby: Archery, Metal detecting, Kitesurfing, Genealogy, Kitesurfing, Calligraphy, Roller skating

Introduction: My name is Gov. Deandrea McKenzie, I am a spotless, clean, glamorous, sparkling, adventurous, nice, brainy person who loves writing and wants to share my knowledge and understanding with you.