How to add dye to an ac system

What is the proper procedure for adding the UV dye that comes in a separate vial (not the kind included with R-134a)?

Here’s where I’d get stuck: Say the system is drawn down and shows a nice vacuum holding on the manifold gauge. I pour the proper amount of UV dye into the yellow service hose on the gauge set and connect the R-134a can. But now I need to briefly loosen the service hose to purge the air from the line. If I do that I lose most of my dye, squirted out everywhere along with the purged air. (Right?)

It seems I’m stuck with two choices: Having a small amount of air in my system or not having hardly any dye in there. Which one I pick I guess depends on the vacuum test. Next time I’ll buy it with the dye in the can.

They make a fitting to do this , but I do not have one .

Worse comes to worse , you COULD , while you still have a vacuum in the system , remove the hose from the vacuum pump ,. Either pour some in the hose as you described . Or stick the end of the hose in some oil ( containing dye ) and open the manifold low pressure valve enough to let it slurp up the dye / oil .

To be safe , after it has ” digested ” the oil / dye , vacuum it down again .

A pain , I know . But you asked .

Wouldn’t I instantly lose my vacuum then? But I believe there’s a shraeder on the pump side of the service hose, so I wouldn’t lose my vacuum. But in that case I couldn’t pour dye in that end either, because it would have nowhere to go.

I like the idea of submerging the hose in the dye. I’d just need to rig up something where I could press on the valve whilst it was submerged, like a nail bent into a tight U shape or something. Honestly I’ve not used this brand new manifold set of mine so I’m not even sure if there is a shraeder on it. I’ll be finding out shortly.

I’m beginning to think this is more trouble than it’s worth. If the vacuum shows a leak, then a little air in there for a couple hours won’t hurt much. And if there’s no leak then I guess I don’t really need the dye in there at present.

I’m interested in this fitting you mentioned. Won’t help me with today’s festivities but I’ve got other cars to do also.

Post by Cusser » Fri Jun 02, 2017 8:06 am

I’m surprised that you didn’t notice lack of cooling when the system was low on refrigerant but still enough in it to engage the compressor.

I have a 2004 Frontier that was low on refrigerant, poor cooling (Arizona) and low pressures on the high side. I’ve had this 5.5 years, and believe that there had never been any AC service ever before. So I bought a can of R134a that contained UV dye (make sure there’s NO SEALERS in it, never use any sealers); note that the dye tends to settle in the can (there’s no oil in the can), so instructions state to add with the can upside down. Note that in my instance that the compressor was still running, my guess was that in 13 years a little refrigerant had leaked out. So I attached the can to my gauge set, bled out any air from the hoses/attached to the service ports, and with the engine OFF held the can upside down and higher than the gauges, and opened up the valves to let the can contents enter, as the can pressure was higher than the static pressure in the AC system. AC has worked fine for last 2 months.

Remember: if you add as liquid (upside down can) with the system running, one must be careful and patient to add liquid refrigerant slowly so no damage is done.

I also have a 1998 Frontier with 218K (mine since 100K) with same AC system, believe that system was also intact at the time; but about 5 years ago I did add about 6 oz. R134a to it (no dye) and that has run fine since. So I think both my Frontiers had lost some refrigerant through normal attrition over the years.

If your car’s air conditioning has stopped blowing cold air, it most likely has a leak. Since refrigerant cannot get out of the system on its own, it must be leaving through a hole somewhere. In order to repair the air conditioner, you will need to find the leak by injecting ultraviolet dye into your AC system.

Step 1

Follow the air conditioning hoses to the low side air conditioning fitting. Unscrew the cap. It will most likely be labeled with an “L”, but if not, it is the fitting further from the condenser (which looks something like a car’s radiator).

Step 2

Attach the tube that is connected to the dye canister to the Schrader valve that was exposed when you unscrewed the “L” cap. You will attach the hose by placing it on the Schrader valve and screwing it on or by pushing down and holding it on.

Step 3

Unscrew the bottom of the dye canister to allow dye to flow into the system. You don’t need much, just a few seconds worth. Read the instructions on the dye leak detector kit to determine exactly how much dye you should put in.

Step 4

Take the hose off of the low side fitting and replace its cap.

Run the air conditioner on full blast so that they dye will escape from the leak.

If you’ve been driving around with hot air coming from your air conditioning vents, it’s definitely time to recharge your AC system. These days, recharging it yourself isn’t too tough a project, and the kits you can buy at your local auto parts store aren’t hard to use. It’s a perfect do it yourself project for the weekend wrench turner. But what if you have recharged your AC system, and you got nothing out of the deal? Or are you in a situation where you have to recharge your air conditioning every season due to a slow leak you can’t seem to trace? If this is the case, you may need to perform a type of leak detection procedure known as a dye test. While there are expensive air conditioning leak detectors available from major tool sellers, in most cases the disposable, over the counter dye-based detection kits work very well. Your car or truck’s air conditioning system operates on a tightly closed circuit of circulating freon. There shouldn’t be even the tiniest leak in the system. With the amount of pressure the AC compressor produces, it doesn’t take much for a tiny leak in the plumbing or hardware to render your system useless and leave you sweating to the oldies on the way to work. Dropping it off for air conditioning service at the local garage can turn into a very spend proposition in a hurry. They do have superior equipment for leak detection, refrigerant collection, and overall diagnosis, but the price tag will reflect the investment the shop had to make in this expensive equipment.

Definition: A dye based air conditioning leak-down test uses a colored dye to find freon leaks in your air conditioning system. Using this test, a colored dye is injected into the a/c system which will be visible under UV (ultra-violet) light at the point of a leak anywhere in the system. The test is performed under full pressure with the air conditioning system closed (sealed as if you were driving under normal conditions). If you’re using the auto parts store version of this kit, you’ll simply inject a small can of UV dye into the air conditioning system through the same charging port you use to add freon. With the dye injected and enough pressure in the system, simply run the AC and use the special UV light to look for any area that is fluorescing. Even a tiny pinhole leak is easy to spot when you’re using this blacklight method. I love it. You’ll also be able to tell which leaks are tiny and which leaks are major, leaving you free to make smart decision in terms of your budget. You may decide to fix the massive link in your condensor right away but leave those two pinhole leaks in the high-side line for another day. Performing a leak test is a good idea if you are thinking of recharging your AC system because recharging a leaking system is a waste of time and money.

How to add dye to an ac system

Read on to learn more about what to look for in an air conditioner UV dye, how to use UV dye for leak detection, and how to properly get rid of it after use.

Whether you are working on a home’s air conditioning unit, a commercial refrigeration system, or a motor vehicle, finding leaks within AC/R systems can be a challenge. Advances in HVAC systems and technology have made this easier over time, but it is still vital to use the right tools for the job when it comes to finding and stopping leaks. Read on to learn more about what to look for in an air conditioner UV dye, how to use UV dye for leak detection, and how to properly get rid of it after use.

What Makes an Air Conditioner UV Dye Effective

As most HVAC professionals know, air conditioner UV dyes work by entering the system and dissolving in the refrigerant. The AC/R technician then shines a blacklight on the system, causing the leaks to fluoresce. Once the leaks are visible, the AC/R technician can assess the issue and determine how best to fix it. An effective AC UV dye should be concentrated, solvent-free, and compatible with the refrigerant gasses in the system. Concentrated dyes are more efficient, and solvent-free dyes prevent damage to hoses, seals, and other parts that are sensitive to solvents. Cool Air Products offers a safe and effective UV dye specifically for use in AC/R systems. Brilliant, our specially-formulated UV dye, comes in easy-to-use syringes that can fit in any technician’s tool kit.

How to Use Brilliant UV Leak Detector Dye

Using Brilliant UV leak detector dye is easy and effective. Simply inject Brilliant into the system, shine a blacklight onto the hoses, and look for fluorescent markers that indicate a leak. Once the leak is discovered, you may be able to fix it using AC SmartSeal or AC SmartSeal External to create a permanent seal. Once the leak is fixed, you can use our Brilliant Remover to spray and wipe away all traces of the fluorescent dye.

HVAC Repair Products That You Can Trust to Get the Job Done Right

Cool Air Products manufactures high-quality HVAC repair products that are designed with HVAC and AC/R professionals in mind. We work with wholesalers around the country to distribute quality repair materials that are 100% non-toxic, eco-friendly, and safe for the user.

Cool Air’s founders are professionals with over 50 years of experience in HVAC, plumbing, and wholesale distribution. We offer AC/R specialty chemicals, leak sealants, performance chemicals, heat absorption products, and more, all using the latest technology available on the market.

Contact Cool Air Products online or by phone at (443)325-7202 to learn more about our products. Be sure to visit our website and follow us on Facebook, Twitter, YouTube, and LinkedIn!

How to add dye to an ac systemBy Alexander Joe Published Jun 13, 2020 at 17:14 PM GMT

Never” is the simple answer to this query.

Let’s see why we probably never need to add refrigerant…

How to add dye to an ac system

The refrigerant that the manufacturers place initially should be enough to last for the whole of your air conditioner’s useful lifetime. Our AC Repair Mt Pleasant SC location sees it as a sealed system which cycles through the air conditioner in copper coils. It has chemicals that absorb and release heat and circulate in a closely packed loop from your indoor AC unit (evaporator) to the outdoor AC unit (condenser). In other words, in theory, your AC should never lose refrigerant.

However, if you believe that you are low on Freon (R-22 refrigerant), you might need to ask a professional HVAC technician to examine the system.

When to call a technician

You need to call a tech if you experience following:

  • Warm air coming from vents
  • Ice on refrigerant lines
  • Higher-than-normal energy bills
  • A frozen evaporator coil
  • A hissing or bubbling sound coming from the refrigerant lines
Freon or thermostat

Even though all of the signs above indicate you’re low on Freon, the problem may lie elsewhere. There could be a number of reasons why your air conditioner is blowing out hot air. The thermostat is the first place you need to look because sometimes units reset to trigger the electronic elements of the system. Once it’s done, set the thermostat to 85 degrees and wait half an hour, then adjust it to 60 degrees and wait for the unit to kick in.

Air filter

Secondly, you could check out your AC’s air filter. If a filter is overloaded with dust and dirt, it is most likely the culprit, i.e., the cause of the malfunction. Now is probably the time to pop in a fresh filter.


How to add dye to an ac system

Finally, turn off the air conditioner, disconnect the electrical power, and inspect the condenser. The condenser is the external (outdoor) part of your air conditioning unit. Its cabinet contains a compressor, fan, condenser coil, and some other controls.

Remove the outer caging of your unit; make sure to not stretch or damage any wires. Use a hose and spray out the AC’s dirt from the inside flushing it outwards, being careful to avoid spraying on any electrical component. Spray the aluminum condenser coils with an all-purpose cleaner and let it sit for 15 minutes so that it can get deep into the grime, and then clean any buildup with water and let it dry.

Don’t try to fix it yourself

If, unfortunately, the problem persists, you need to call a professional HVAC technician – there might be a leak!

Remember that your air conditioner’s refrigerant is toxic, i.e., it is poisonous. It can cause serious breathing problems and other complications if your are directly exposed to it. Therefore, do not try to fix things yourself.

If the HVAC technician is certain of Freon leakage, you should make sure that they plug the leakage. Some of them might just refill the unit and charge you for the whole process, which is both expensive, and over the medium- or long-term, unhelpful. Somebody will have to come again to fix the problem.

Steps the technician has to follow:

  • Turn off the system from the source.
  • Locate the leak.
  • Attach the repair kit.
  • Seal the leak.
  • Prepare the system for recharge.
  • Add Freon.
  • Test the system.


Once the leak is located, make sure the technician uses the DV dye. If you have had your air conditioner for twelve or more years and the tech suggests you add a new Freon, give yourself some time to think about it. It could cost you $1000, or even more, depending upon the size of your AC.

(813) COLD-AIR
For 24 Hour AC Repair with

Your home’s AC system is extremely important during the hotter months of the year, as it helps keep indoor temperatures cool. When it experiences refrigerant leaks, though, it can’t bring enough cool air in; leaving you hot and sweaty, and costing you a ton in energy bills.

If you don’t want to be left dealing with scorching temperatures during the hot summer months, it’s important to know how to check for freon leaks in a home AC system.

Disclaimer: Contacting an AC Repair company is the best method for solving your AC problems, including refrigerant leaks. If you have no experience in handling AC repairs, don’t risk causing more damage. We take no responsibility for the information provided below, and highly recommend calling a professional.

How to Find a Refrigerant Leak in Your Home AC System

  1. Dye Detection

One of the more effective ways to check for a refrigerant leak in your air conditioning system is to conduct a dye test. This process involves sending fluorescent dye into your HVAC system. After it has enough time to circulate, the dye will pour through any leaks that are present.

Then, with a detection lamp, you can scan the HVAC system and pinpoint where the dye leaked out. This entire process shouldn’t take you longer than several minutes, but it does involve investing in specialized equipment. If you don’t have the time, money, or expertise to execute this dye test, you should contact a professional AC repair company. They can perform this dye test safely and quickly.

There are many advantages to this dye test compared to the other testing methods. For one, you can identify every leak quickly within your HVAC system. Leaks can also be detected at a distance, as long as enough light from the detection lamp is administered. Additionally, this dye test can be performed when your AC unit is running or not.

Another useful and straightforward leak detection method you can try involves using an electronic device. It allows you to scan across refrigeration components outside of your household. When a leak is detected, this electronic device will sound an alarm that’s easily recognizable.

The only downside to this method is leaks can only be identified in specific areas, where the electronic leak detector touches refrigerant components. These electronic leak detection devices can also be pricey, and you’ll need to undergo some brief training to learn how to use them correctly. Another thing you have to account for is ensuring the electronic detector is compatible with the refrigerant you’re using. Otherwise, the detector will not go off when it comes across leaks.

Again, if you want to save yourself the trouble of investing in one of these devices, you can always contact an AC services and repair company to perform this test. They can execute it in a cost-effective manner and save you from a costly AC repair.

There are many leak detection tests that homeowners and HVAC technicians like to use, but the nitrogen leak detector test is one of the more popular. It can cost more than other methods, but it provides accurate results that you can rely on.

First, the remaining freon in your system will need to be removed. Then, nitrogen is pumped back into your home AC system. Since nitrogen is held at a higher pressure than refrigerant, it will make audible noises where leaks are present.

Then, all that’s required is listening for these audible sounds and then marking these areas off. You’ll also know if leaks are present if you monitor the nitrogen using pressure gauges. If these gauges show significant changes in pressure, you know a leak is present.

If you plan on testing your HVAC system for leaks without professional assistance, one of the best methods to try out is the soap bubble test. This test is rather simple to carry out. All you need to do is mix up some soap with warm water. Then, you’ll need to mix this solution for several minutes.

After it has been stirred up enough, send it through your AC refrigerant system. If there are leaks in your system, air bubbles will be visible. You can then mark these areas so that an HVAC technician knows precisely where patches are required.

It’s crucial that you don’t add any corrosive elements to this air bubble mix. If you do, these elements could wear down your refrigerant components and leave you with costly repairs. You also should be careful about not applying enough air bubbles, because once this solution enters the system, it may be hard to tell where exactly the air bubbles are coming from.

Again, if you’re not familiar or experienced with AC repairs, we highly suggest contacting an AC repair company to check for refrigerant leaks.

When a refrigerant leak is present in your AC system, sometimes oil will also leak out. This substance is pretty simple to detect given its thick, dark consistency. It also has a potent smell that is easily distinguishable, even if you’re far away.

If you suspect a leak in your system, start feeling around different AC components. You’ll want to wear protective gloves when performing this step, so you don’t get your hands dirty or cut them on a sharp part.

Feel around different components and keep checking your gloves for visible signs of oil. If an area produces a lot, chances are there is a leak that needs to be repaired right away. If you don’t have protective gloves, you can also use cloth. Make sure it’s light colored, so if oil is present, it will be visible.

Detecting AC Refrigerant Leaks

Dealing with AC refrigerant leaks can be stressful, as they prevent your HVAC system from working at an optimal level. If you’re thinking about how to find a leak in your home AC system, you don’t have to go into a frenzy. You just need to try a leak detection method that works for your budget, or you can try a combination of methods to ensure all leaks are identified.

Only then will you know where leaks are and can take the necessary actions of patching them up. Just make sure you exercise extreme caution and don’t be afraid to seek 24 hour AC repair assistance if you’re not comfortable with a detection method. Some steps may even need to be carried out by a licensed technician legally – so brush up on these local laws to avoid costly fines.

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Tracerline® dyes are co-solvent free and can be safely added to the system. They won’t affect the system’s lubricant properties or change how the equipment works. Tracerline® dyes can find the smallest and most problematic leaks that would otherwise be impossible to detect.



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How to add dye to an ac system



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How to add dye to an ac system


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How to add dye to an ac system


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How to add dye to an ac system

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One thing I haven’t mentioned yet is putting refrigerant oil in the system.

You normally do this when recharging the system after replacing one of the major components. This is tricky. The service manual normally tells you how much refrigerant oil should be added with each major component replaced on the AC system. You need to be very careful during this process.

Many people ask what refrigerant oil actually is: Basically, it is a specialized oil meant to be used in your air conditioning system that is engineered to run smoothly through all the moving parts.

*For more info on recharging your AC system, you can try this page.

The thing is, most replacement components, such as compressors, often come with the prescribed amount of oil already in the part. If you add oil on top of this, you might saturate the system and it won’t work as well.

In addition, it’s not a good idea to mix R134a refrigerant oil with R12 oil. This becomes an issue if you’re retrofitting an AC system. On top of that, it’s difficult to add oil to the AC system with DIY tools. Professional AC equipment comes with provisions to add the correct amount of oil with each charge. Off-the-shelf cans sometimes come with refrigerant oil in them as well.

My point here is that if you want to err on the side of caution, don’t add any oil to the system. It’s worse if you add too much and cause a problem. Look for refrigerant cans that have oil already in them. This will be your best bet. Otherwise, make sure you measure out the correct amount of refrigerant oil and ensure it is the correct type before you add it to the system. Here is a video on recharging your AC system, in which I add refrigerant with oil:

I’ll say it again: make sure you are wearing safety glasses when you work on AC systems.