How To Find Leak In AC System Car?

There are several things that can go wrong in your car. Components can become faulty, malfunction, or stop working entirely. That is why regular car inspection is essential for car owners. One of the common issues you will encounter as a car owner is low fluid levels in one or more system components. A low fluid level in the AC system means there’s a leak somewhere in the system.

Below, you will learn how to find leak in AC system car if you suspect your air conditioning refrigerant is low. And how to fix these leaks and the cost of repair.

how to find car ac leak without dye

Symptoms Of Leaks In Car Air Conditioning

The first step to identifying a leaking air conditioning system in cars is to know the signs of a leaking AC. Watch out for the following signs to find where the leak is happening:

There is oil stains or moisture around the AC lines

Another sign that your car’s air conditioning system is leaking is an oil stain or moisture around the air conditioning components or lines. Your AC compressor, condenser, and lines should be dry and clean. If you see oily stains or moisture in these areas, you have refrigerant leaks in your hands.

Your car AC is not working properly

If you start noticing that your car air conditioner is not giving you that cold feeling as it used to, it’s a sign that something is not working correctly. That is usually a sign that your AC refrigerant is leaking. Low refrigerant levels weaken AC performance.

A hissing or bubbling noise coming from the AC system

Hissing noise from the car air conditioner is a clear indication that the refrigerant is leaking from somewhere in the system. Please remember that a bubbling or hissing sound can also come from a vacuum leak in the engine. However, you have a refrigerant leak if you only hear the hissing or bubbling noise when you switch on the AC.

Your AC is blowing warm air

If warm or even mildly cold air is entering the cabin instead of chilling cold air when you turn on the air conditioning system, it’s a clear sign that something is wrong with the AC system—which, in most cases, means you have low refrigerant levels. 

You are perceiving a strange smell

Finally, another sign that you have an AC leak is if you perceive a strange smell coming from the air vents. If you start perceiving a pungent or musty smell from the air vents when you turn on the AC, it’s time to pay your mechanic a visit.

If you experience any of these signs, then you may be wondering, how do you detect leaks in an air conditioning system. It’s one thing to know you have a leak and another to detect where it is coming from.

How To Find Leak In AC System In Car

Now you know the signs of a leaking freon, how do you detect where the leak is coming from? If you notice the above signs and can say for sure you have an AC leak, there are a few ways to find out where precisely the refrigerant is leaking from. Let’s see these various ways below.

How To Find Leak In AC System Car

Visual inspection

The first and easiest way of finding where your car’s AC refrigerant is leaking from is through a visual inspection. Visually inspect the air conditioning system components, such as the compressor, condenser, and refrigerant lines. If there’s a leak on any of these components, you will see a PEG or refrigerant oil residue. Slow AC leaks are easy to trace because they leave oily residues on the leaking area.

Run AC leak detector test

Another efficient way to confirm if and where your AC system is leaking from is to perform the UV dye AC leak detector test on the air conditioning system. To use this method, get UV light and shine it into the AC. Freons are usually mixed with UV dye that will illuminate if they spot a black light.

Hence, if you see any traces of dye around any air conditioning components, it could mean you have refrigerant leaks in that area. Much like the soapy water method, the AC leak dye UV light method does not detect leaks on the evaporator and front compressor seals. 

Spray soapy water on the AC components.

The next easy option is to spray soapy water on the suspected areas. Get a bottle of water and mix it with detergent. Then gently put it in a spraying can and spray through the suspected areas while the AC is on. You will see bubbles if the soapy water gets to ruptured, damaged, or leaking areas.

This is one of the efficient methods if you are asking how to find car Ac leak without dye. However, while this method is effective, it does not detect leaks on the AC evaporator and front compressor seal.

Perform AC pressure test

There’s also a chance the problem you are dealing with is not an AC leak. An air conditioner pressure test will help you confirm whether it is a leak. Use the AC pressure tester to gauge the pressure levels on the low and high refrigerant lines. If, however, the reading falls outside the specified pressure range, it could be an indication of a small leak.

Using a sniffer device

If visual inspection, soapy water, and UV dye test prove abortive, use a sniffer device. The sniffer device is designed to quickly find the chemical particles of freon. This means that this device will detect air conditioner refrigerant leaks anywhere around the system. In any case, you have to clean the AC system components before using this device as dirt and debris will prevent it from working effectively.

Scan the AC system for leaks

Another option is to scan the air conditioning system using an electronic leak detector. The electronic leak detector can detect the presence of halogen gasses. If the scanning is positive, it could mean you have a leak somewhere in the system.

Get professional help

It’s one thing to know you have an AC leak, another to detect where the leak is coming from, and another to fix the problem. If you have tried the above methods and, yet have no results, contact an expert HVAC technician to take a closer look at your car’s AC system.

Expert HVAC technicians know their way around car air conditioners. So, it won’t take them much time to detect a leak and also proffer a quick fix.

However, in all fairness, AC repairs are best left for professionals to handle unless you are experienced. If you are a novice, you can end up creating more damage to the system.

Why Are Car AC Leaks Hard To Find?

Unlike transmission fluid, brake fluid, and motor oil, car air conditioner refrigerant is a colorless fluid that cycles through liquid and gaseous states within the system. It rarely leaves any visible streaks and trails because of its unique properties, which is why they are hard to find without a trained eye.

Fortunately, using the above methods, you can still trace the leaks even if you are not a trained technician.

How Much Does It Cost To Fix A Car AC Leak?

The car air conditioner may leak in one or more places and you will need to replace all faulty components to address it. That said, the precise amount of finding and fixing the AC leak largely depends on the affected part, the ease of accessing it, and the cost of replacing it.

However, on average, car AC leak repair costs between 150 and 500 dollars. This means you should expect to spend between 100 dollars to 1500 dollars, depending on the faulty component.

Final Words

If you see any of the most common signs of AC leaks in cars above and suspect you have a leaking AC refrigerant, find where it is looking from by visual inspection. If you cannot detect the leak with visual inspection, try other methods I explained in this article.

If, however, you are not a DIYer, don’t sweat it. Contact your dealership or local mechanic to find and fix the leak.

Osuagwu Solomon

Osuagwu Solomon is a certified mechanic with over a decade of experience in the mechanic garage, and he has over five years of experience in the writing industry. He started writing automotive articles to share his garage experience with car enthusiasts and armature mechanics. If he is not in the garage fixing challenging mechanical problems, he is writing automotive repair guides, buyer’s guides, and car and tools comparisons.

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