What Causes the AC System to Leak?

Your car’s air conditioner is responsible for keeping the interior cool and comfortable on hot days. However, in order to do that, you need the right level of refrigerant in the system. If your refrigerant is low, the air conditioner may blow warm or hot air. A special switch is designed to sense when there isn’t enough pressure (or when pressure is too high) and disengage the AC compressor clutch, which operates the compressor to pressurize the system.

Causes of low refrigerant

There are a number of potential causes for low refrigerant in your car’s AC system. Some refrigerant is lost naturally over time. It takes years, though, so if your car isn’t that old or the system has been recharged recently and is now blowing warm air again, chances are good that you’ve got a leak somewhere.

There are two causes of AC system leaks – age and moisture. While much of your air conditioning system is made of metal, including the high pressure lines, rubber is still used throughout. You have rubber O-rings, grommets, lines and more. The problem here is that rubber degrades over time and with exposure to heat and moisture. As that wear accelerates, the affected part will fail. Something as simple as a degrading O-ring can cause you to loose refrigerant surprisingly quickly.

Other sources for a leak include:

  • Failed Seal
  • Failed Hose

That’s not the end of it, though. If you have a leak in your air conditioning system, it’s possible that moisture has entered the lines. Moisture in an automotive AC system is very bad. It mixes with the refrigerant left over and creates a type of acid. Once your system is contaminated with moisture, it’s very possible that other components will be affected and require replacement. This can include:

  • The receiver/dryer
  • Accumulator

Detecting the leak in a timely manner is vital. If you wait too long from the initial point of AC malfunction, moisture will enter the system. Locating the source of a leak depends on the type of system you have. Some are pre-injected with UV dye, while others will have to be charged with dye. In both cases, a black light held over the engine will show where the refrigerant is leaking.


Next Step

Schedule AC is not working Inspection

The most popular service booked by readers of this article is AC is not working Inspection. Once the problem has been diagnosed, you will be provided with an upfront quote for the recommended fix and receive $20.00 off as a credit towards the repair. YourMechanic’s technicians bring the dealership to you by performing this job at your home or office 7-days a week between 7AM-9PM. We currently cover over 2,000 cities and have 100k+ 5-star reviews... LEARN MORE

SEE PRICING & SCHEDULING

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Recent AC is not working Inspection reviews

Excellent Rating

(991)

Rating Summary
932
25
7
11
16
932
25
7
11
16

Jeremy

20 years of experience
437 reviews
Jeremy
20 years of experience
Toyota Tundra - AC is not working - West Palm Beach, Florida
Jeremy was awesome. What a great experience. I will definitely use this service again. Thank you so much
Dodge Grand Caravan - AC is not working - Boynton Beach, Florida
Jeremy is a very nice guy, immediately gets to work and resolve the issues. This is the second time he’s worked on vehicles for me and each time was an excellent experience. Highly recommend him

Peter

25 years of experience
437 reviews
Peter
25 years of experience
Scion xA - AC is not working Inspection - West Hills, California
Peter has an awesome personality. Very knowledgeable and friendly. Definitely no BS from him. Very honest.... Will I use him again? Definitely. Will I refer him? Absolutely! Thank you Peter!
Mercedes-Benz ML500 - AC is not working Inspection - Reseda, California
Peter took his Time to check out and diagnose my vehicles problem. I was able to add some Freon and the cooling system is most definitely getting colder. I’m gonna drive it for the next few days as recommended and see where I’m at and go from there. Thank you for your time Peter

Matthew

33 years of experience
1020 reviews
Matthew
33 years of experience
Acura RDX - AC is not working - Newport News, Virginia
Matt is always so pleasant to work with. I appreciate his knowledge and attention to detail with my car. Thank you Matt!
Chevrolet Impala - AC is not working - Newport News, Virginia
Matt was on time and during the discussion with him he showed a great deal of knowledge about my a/c issue. I book this repair this weekend and look forward to Matt repairing my car. Thank you Matt

Bryant

12 years of experience
512 reviews
Bryant
12 years of experience
Jeep Patriot - AC is not working - Indianapolis, Indiana
Always great service with Bryant, he explains all he is doing as well as what else needs to be complete. I will be scheduling my next visit from him soon.
Ford Expedition - AC is not working - Indianapolis, Indiana
Second time using Bryant and he was, in both instances, able to diagnose and locate the problem. What I find particularly great is that both issues were very easy and inexpensive fixes. Bryant was very candid about the problem and offered to show me how to fix the issue if I wanted to do it myself. I just had him make the repair, which was done quickly. He also found an alternative part that saved me from having to order it online and wait a few days for the repair to be made. Bottom line, Bryant does what’s right and is honest about what the problem is. Anyone could have told me its a $1,200 repair and I wouldn’t have known differently. Use Bryant if you want honesty and great work.

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

Related articles

4 Essential Things to Know About Your Car’s Seat Warmers
Some Some vehicles come with car seat warmers, which heat up the seat with the push of a button. Normally the buttons are located on the side of the driver and passenger door. In some vehicles, just the bottom of...
How to Buy a Good Quality A/C Compressor
The A/C compressor helps regulate the flow of refrigerant throughout the A/C system. High quality A/C compressors are new and easy to install.
Symptoms of a Bad or Failing AC Air Filter
Common signs of a clogged AC air filter include reduced airflow from AC vents, less power coming from the engine, and increased dust in the cabin.

Related questions

Leakage near the radiator fill cap and the AC/Heater doesn't work

It sounds like you have 4 issues: Coolant leak Possible issue with the water pump An unexplained, but transitory noise HVAC faults. The coolant leak is the most important one to fix first because a coolant leak can...

A/C problem - 2007 Honda Civic

Hello. It is possible to damage the compressor by introducing liquid refrigerant. The compressor is designed to compress vapor or gas, not liquids which indeed are not compressible. If your system is not working right now, a possibility is you...

No heat,defrost or air coming from front a/c vents

Hello - there a couple of possibilities here for this problem: the blower motor resistor pack, or the fan switch portion of the HVAC control itself. The blower motor resistor pack regulates fan speed in the Low or Medium positions,...

How can we help?

Our service team is available 7 days a week, Monday - Friday from 6 AM to 5 PM PST, Saturday - Sunday 7 AM - 4 PM PST.

1 (855) 347-2779 · hi@yourmechanic.com