Usually when your vehicle is leaking something, there is an indication of the leak before a problem with the equipment arises. For example, if your car is leaking antifreeze, there are usually drips, puddles, burning smells or steam letting you know there is a problem long before your car actually begins to overheat. Your goal is to simply take the time to check over your engine and vehicle every few weeks and look for these indications of a leak. Oil leaks are similar in that they usually show signs of a leak before any actual damage is caused.
What is car refrigerant?
On the other hand, refrigerant leaks in your air conditioning system will do you no such courtesy. Refrigerant is actually a brand name of a refrigerant, like Kleenex is to a tissue. There are many different type of refrigerants used depending on the system, and surprisingly enough the air conditioning system in your car actually works much like the system in your refrigerator. In both cases the goal is to remove heat from inside of a closed chamber, either your freezer, or the passenger compartment of your vehicle. Through a compressor, an expansion valve, and a series of heat exchangers, a refrigeration system can take the heat inside a closed space and put it outside. The heat is transferred from inside to outside through a working fluid.
This working fluid needs to have very particular characteristics in order to function properly in the refrigeration system. This working fluid, or refrigerant, needs to remain a liquid or expand into a gas at just the right temperatures and pressures to make sure the equipment is kept safe in your air condition system and the heat transfer process actually takes place. The most common refrigerants used today are kept at high pressures in the systems they are used in to ensure they work properly. This makes these refrigerants turn very quickly into a gas if they are exposed to normal temperatures and pressures that we live in.
Not only does the refrigerant in your car turn into a gas if it is let out of the system, its colorless and odorless as well. All of these characteristics make it very difficult to see, smell or hear if you have a refrigerant or refrigerant leak in your vehicle.
How do I find my car’s refrigerant leak?
Mechanics use a few different techniques to help discover where refrigerant is leaking from in air conditioning systems. The most common practice is to add a special dye to the air conditioning system. This dye is usually very difficult to see with the naked eye, but will glow brightly and obviously when illuminated by an ultraviolet (UV) light. To discover where your refrigerant leak is coming from, add UV dye to your air conditioning system and enough refrigerant to ensure the compressor actually turns on. While the engine is running, have a friend turn on the air conditioning and blower. While he turns the AC on, watch the front of the compressor in your engine bay. The belt should always be spinning the AC compressor pulley, but right when the AC is turned on, the front of the compressor pulley should begin to turn as well. If you can see this happen, then you can ensure refrigerant, and your newly added dye is circulating through your air conditioning system.
After leaving the motor running for a few minutes, up to a few days of driving time with the air conditioning on, park your car in a very dark place like a garage with the lights off. Shine your UV light around the engine bay focusing on the air condition lines around the compressor and the condenser at the front of the car. If you don’t see where the dye is leaking from, don’t forget to check the expansion valve and dryer under your hood. If you still haven’t found the leak, check inside your vehicle under the dash. The evaporator will be under your dash usually just after the fan blower motor and the heater core. This may be more difficult to find but you may find dye in the air vents, on the carpet, or on the cabin air filter.
How do I fix a car refrigerant leak?
If the whole procedure with the dye, a friend turning your car on and off and poking around in a dark garage with a funny flash light doesn’t sound like your kind of fun, considering using BlueDevil Red Angel Stop Leak to inject new refrigerant into your air condition system. Not only will you get 2.5 ounces of refrigerant in an easy to use delivery system, but you also get 2 ounces of BlueDevil A/C stop leak agent. The leak sealing agent will act as a lubricant for your air conditioning system until it encounters a leak. At the leak point, the temperature change there will cause a chemical weld sealing the leak guaranteed! There is no need to spend time or energy poking around to discover your air condition system leak with BlueDevil Red Angel A/C Stop Leak. Just connect the included coupler, empty the can into your air condition system and enjoy a leak free air conditioning system.
BlueDevil Products can be found on Amazon.com or at AutoZone, Advance Auto Parts, O’Reilly Auto Parts, NAPA, and other major auto parts retailers.
64 responses to "How Can I Find My Refrigerant Leak?"
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Hello I only noticed that I needed to add Freon to my car because the light came on. It came on the second day I had it. The light didn’t come back on until This Monday past. However two days later the light came on again and I left to take my son to school when I got back I see the ground and notice it’s wet. I was already going to look to make sure I didn’t need the Freon but when I lifted up the hood it was more than halfway gone so I added more Freon and went to work after work I noticed the ground was wet and lifted up the hood and it was completely empty except for what I could see still at the bottom going into the hose. So is it too late to buy Blue Devil? or can I still but it and add Freon and then add the Blue devil?
Dorothy-
You can still use the Red Angel A/C Stop Leak to stop your refrigerant leak. You will add the Red Angel first and then recharge the A/C system with the proper amount of refrigerant.
Feel free to contact us at 888-863-0426 with any questions.
Thank You!
-BDP
Can I use Blue Devil to plug a leak in my central A/C system? I’ve already replaced the coils so I know it isn’t there.
Daniel-
We recommend applying Red Angel A/C Stop Leak to seal your leak. You should be using the 2 ounce bottle of Red Angel (http://store.gobdp.com/a-c-stop-leak-49496/).
Feel free to contact our tech support team at 888-863-0426 with any questions.
Thank you!
-BDP
My mechanic told me to never use these sealing products because they almost always cause more expensive problems. How do I know your product isn’t going to seal the wrong thing and just stuff up my pipes?
Ron-
Red Angel will not clog or affect any other components of the A/C. During the injection process, drying agents prevent any unnecessary sealing activity. Also, Red Angel will not clog or damage the recovery unit. It is removed with the reclaimed oil. Feel free to contact our technical support line at 888-863-0426 with any other questions.
Thank you!
-BDP
My ac stopped working. I was told that it was leaking behind the dashboard. Can I buy blur devil to repair it
Brittany-
Based on your description, we would recommend using the Red Angel A/C Refrigerant Stop Leak, found here on our website: https://gobdp.com/product/ac-refrigerant-stop-leak/. Feel free to contact our technical support line at 888-863-0426 with any other questions.
Thank you!
-BDP
Dorothy, after reading your response, it appears that you are confusing an air conditioning refrigerant (Freon) leak with an engine coolant (antifreeze) leak. From your comments you mention the ground being wet and you could see it was halfway gone then completely empty. Sounds like you are referring to the coolant reserve tank.
I had a mechanic add Freon a few days ago. The AC is back to not working. I’m taking it in to see if or where the leak is. If they tell me it is a leak, can I just add the Red Angel and then get it recharged?
Scott,
Absolutely. If they find your Freon level low again then you have a leak and you can use BlueDevil Red Angel A/C Stop Leak to seal the leak. Red Angel is available in either an easy to use aerosol (http://store.gobdp.com/a-c-stop-leak-aerosol-00222/) or in a liquid form your mechanic can inject into the system (http://store.gobdp.com/a-c-stop-leak-49496/).
Hi, I have an 01 Honda accord and 5 months ago I paid $700 at shop to have evaporator replaced and expansion valve replaced and recharged. They said everything else was fine. Air worked great til a few weeks ago started blowing hot. I checked low pressure and was almost none so I recharged it and it was ice cold but 3 days later was hot again. I have tried to charge it again and same thing happened. Each time the low pressure is real low so I’m thinking it must be a leak. Does this sound like blue devil will work or should I take back to the shop?
Kristen-
Based on your description, we would recommend using the Red Angel A/C Stop Leak & Conditioner, found here: http://store.gobdp.com/a-c-stop-leak-aerosol-00222/ . As long as the system can hold 5 inches of vacuum for 25 minutes, you should be able to see some great results from the product.
Thank you!
-BDP
Greetings. Have had the vehicle in a couple of times for the A/C not blowing cold. The mechanics have used the UV dye method and thought they found the leak but I get it back, and a couple of days later there is a hissing sound and the A/C loses its cool air. Any suggestions?
Steve-
We recommend adding a can of the Red Angel A/C Stop Leak (http://store.gobdp.com/a-c-stop-leak-aerosol-00222/) to your system. After the product is added you should recharge the Freon to it’s proper level. This should create a chemical weld at any leak point within the A/C system.
Thank you!
-BDP
Just wanted to update I bought the aerosol red devil and recharged and it’s as good as new! It’s been a week and it hasn’t leaked at all. Very impressed because I tried ac pro which didn’t work a bit but your product works as claimed. Saved me a lot of money so thank you!!
I’ve read elsewhere that a leak from the compressor cannot be sealed using an add-in product. A shop told me the compressor has a leak, and the low refrigerant level prevents the compressor from running. Yet there remains some refrigerant in the system, as evidenced by hissing when I press on a service valve. So I have to decide whether to try recharging, or replacing the compressor, etc. (I hate throwing good money after bad.) What do you recommend?
Jay-
Based on your description, we would recommend having the compressor replaced. Doing a recharge may alleviate the problem for a little while but, if you are continuing to lose freon, would not completely fix the problem. A replacement of the compressor would be your best option.
Thank you!
-BDP
I have read all the questions and responses on this site and I have to be completely honest…im a little excited about this product!
I have been an H.V.A.C. certified technician for the past 14 years and kind of a “fixit” guy for the past 22 years, and I have chased my “fair share” of those elusive horrible leaks sometimes having more than one in the same system! I recently had to replace the motor in my truck, therefore in the process had to evacuate and rebuild and reseal the entire system as I replaced my heater core in this rebuild, and like a dummy didnt even check my evaporator in this entire 7 hour process of disassembling my dash to get to it ….. (FAIR WARNING!!!! NOT A JOB FOR THE AMATEUR). Anyways to get too the point of this rant, I noticed as I was vacuuming down the system I definately had a leak so I nitrogen charged the system to check all my fittings easily accessible and found no leaks by bubble test. SUCK!!!!!! this means its probably in the evaporator or condenser (which is much easier too access on the front of the truck). So too the point….. to anybody reading this…BY ALL MEANS TRY THE RED ANGEL FIRST! I mean at least give it a try because you have nothing too lose and if at all possible try to do it yourself or find a H.V.A.C. guy or girl that can maybe coach ya through it cause you can save countless $ and if it does not work then well I cant tell ya sorry sucker your just outta luck! But I can tell ya if it does work then thats awesome and youve saved some major coin! So now I think im gonna get my hands on some and take the most least evasive and least costly attempt before taking more drastic measures. Besides seems like a pretty good product from what I hear!
FIXIT GUY OUT!!!!!
I tried putting freon in my grandparents car and can hear it hissing back out from the grill area at the front of the car. Any suggestions as to how I can help them
Brenda-
Based on your description, it sounds like the vehicle is losing refrigerant. We recommend using the Red Angel A/C Stop Leak & Conditioner, found here: http://store.gobdp.com/a-c-stop-leak-aerosol-00222/ . The product would treat leaking condensers, evaporators, connection hoses, gaskets and o-rings.
Thank you!
-BDP
Have recently added one can of freon to my 90 Chevrolet truck to see if it would take a charge the next day empty so I purchased another can with dye in it the next day still had pressure no signs of dye so I added another can to finish the charge one week later still no signs on dye except at low port where it was added did not check under dash
Jim-
If the leak is somewhere behind the dash then it will be nearly impossible to detect with the UV leak detection dye. W recommend adding a can of Red Angel A/C Stop Leak (http://store.gobdp.com/a-c-stop-leak-aerosol-00222/) and then following it up with the proper amount of R-134a to fill the system. This will stop any leaks within the A/C system and allow your refrigerant to stay level for proper cooling.
Thank you!
-BDP
Hi my 2005 f150 5.4
The low pressure service cap is stripped i tighten it then it gets loose does this cap hold pressure
Edward,
The cap on the low pressure port of your system does not hold pressure. There is a valve under the cap much like the valve in the valve stem in your tires that should hold pressure in your system. The cap you’re talking about is just designed to keep dust and debris out.
Thanks again for your question!
-BD Auto Pro
I’m not sure if I have a leak but when I get out my car I smell freon strong lasting for about an hour or so before dissipating (after I was running it for about 5 hours in the Vegas heat) my air in the car blows cold but every so often blows air (not cold or hot) for about 30-60 seconds at least 2-3 times in a 5-7 hour period then blows cold again. I never smell anything in the car always outside. Should I take my car to a shop to have it checked or use the Red Angel first?
Sha-Na,
Thanks for your question about your car. based on your description of your air conditioning, it doesn’t sound like you have a refrigerant leak in your car. The refrigerant in your air conditioning system doesn’t have an odor to it so the smell you mentioned must be indicating another leak. Oil leaks have a distinct oily smell and coolant leaks will often smell sweet. You can try checking your fluid levels to see which might be leaking. If you think you have an oil or refrigerant leak, you can use the appropriate BlueDevil Stop Leak product to seal that leak and get things back to normal.
Thanks again for your question!
-BD Auto pro
My car ac system will not hold a charge at all, it seems to have a large leak. The system is at zero pressure. Is it safe to charge the system with refigerant with dye without pulling a vacuum, and get the compressor running so I can find the leak, or will it damage the system to run it that way?
David,
Thanks for your question about your AC system. Depending on how old your car is, most R-134a systems have low pressure cut off protection so they won’t let the system get damaged from running on low pressure. If your compressor isn’t turning on once your system has leaked all the refrigerant out, then your car has this feature and it is safe to charge the system without pulling a vacuum to add dye and try to find your leak location.
Thanks again for your question!
-BD Auto Pro
How do u recharge your ac to u have to take it to the
shop?
Brandy-
Yes, you make take it to any shop that does A/C recharges. The other option would be to purchase the R-134a through your local auto parts store and adding it yourself.
Thank you!
-BDP
My a/c recently stoped blowing cold air. I have try the little a/c charger thing from autozone but it didn’t help at all. Also know there is a small leak but have no clue where? Will that blue devil stuff help me at all?
Brittany-
Based on your description, we recommend using the Red Angel A/C Stop Leak & Conditioner, found here on our website: http://store.gobdp.com/a-c-stop-leak-aerosol-00222/ . As long as you are not losing refrigerant too quickly, you would be a great candidate for the product.
Thank you!
-BDP
My air was blowing out hot so i recharged it with arctic from auto zone. My a/c blew cold for a couple days and now ita back to blowing hot. I dont hear a hissing sound but i think it may be a leak because i just charged it. I dont know what to do at this point.
Jazmine-
Thank you for your question. Based on your description, we recommend using the Red Angel A/C Stop Leak & Conditioner, found here on our website: http://store.gobdp.com/a-c-stop-leak-aerosol-00222/ . As long as you are not losing refrigerant too quickly, you would be a great candidate for the product.
Thank you!
-BDP
Hi a couple days ago I realized my Freon level was low, we checked and found that the evaporator had a leak but because of time constraints I just had the system topped up however the next morning it was low again. Is this leak to large for your product to work and also will this system cause any problems to the expansion valve, drier and swashplate compressor.
Kevin-
Red Angel A/C Stop Leak is 100% safe to use in your A/C system. The product is non clogging and has no possibility of negatively affecting any of the components of the A/C.
We recommend injecting the Red Angel and then following it up with the proper amount of refrigerant.
Thank you!
-BDP
Kevin-
The Red Angel A/C Stop Leak & Conditioner is not recommended for systems that lose more than one pound of refrigerant per day. Based on your description, it seems you may be losing refrigerant a little too quickly for the product. Unfortunately, a hard part repair may be your best option.
Thank you!
-BDP
My van was is blowing hot so I recharged the system an noticed the shatter valve was leaking I replace it and recharged it again. The next morning it was blowing hot again. So I know it has a leak somewhere else. Would Blue Devil work on this situation?
Jason-
Based on your description, we recommend using the Red Angel A/C Stop Leak & Conditioner (http://store.gobdp.com/a-c-stop-leak-aerosol-00222/) for your refrigerant leak. As long as the leak is not coming from the compressor and you are not losing refrigerant too quickly, you would be a great candidate for the product.
Thank you!
-BDP
I used 4 ounces of another product on the market. It did no good . Will the red angel product do any better and is it all right to add in on top of the other. Will it work? I am losing refrigerant over night. The a.c. will work all day after charging but be hot the next day. Thank you
Kelly-
Based on your description, we recommend flushing the A/C system first, prior to adding the Red Angel A/C Stop Leak. Not knowing the chemical formulation of the other product used, we would not recommend mixing the two.
Thank you!
-BDP
Can i fill up my benz compressor with freon and the compressor leak it all out in ten min. I can hear it coming. Hissing from that area.
Joseph-
Unfortunately, the Red Angel A/C Stop Leak would not be intended for a compressor leak. A hard part repair may be your best option.
Thank you!
-BDP
My 97 grand am runs air for a Day. The next day it’s blowing hot out Freon in did the same thing replace a/c compressor still leaking out can I use the red angel
Eric-
Thank you for asking about your Pontiac Grand Am. Based on your description, we recommend using the Red Angel A/C Stop Leak to help stop the loss of Freon and return the A/C to normal functionality. Feel free to contact our technical support line at 888-863-0426 with any other questions.
Thank you!
-BDP
Just filled my system AGAIN. Can I add red angel to an already full ac?
Joe-
You would want to add the Red Angel A/C Stop Leak to a system that is evacuated or partially depleted. You may top if off with refrigerant after the product has been added.
Thank you!
-BDP
Can a leak in the dash cause health issues? I was told I have a very small leak in my dash, should I be concerned?
Lisa-
Yes, refrigerant exposure to your heart and lungs can be hazardous. There are several articles online that explain the health issues associated with breathing in R-134a. We recommend sealing the leak with the Red Angel A/C Stop Leak, and then topping it off with R-134a.
Thank you!
-BDP
For about a month I’ve noticed the a/c in my 2011 GMC Terrain tends to lose it’s coolness. Instead of taking it to the shop, I decided to buy and add a can of Avalanche ac refrigerant myself. Worked great for a couple weeks and my air was cold again. But then I noticed that the system was blowing fan like air and not getting cold. So I eventually added more refrigerant. Seems like after roughly 3-4 days I add another can. I’ve tried about 3 brands and yet I still seem to lose refrigerant. I’m on my 4th can in a month! It’s obviously leaking but I’m not quite sure where. I’ve seen a few drops of refrigerant, not antifreeze, underneath my vehicle towards the passenger side. What do you recommend? Also, I think I’m in need of a new blower because when I turn the fan on high it gets louder. Is this related? The fan blower has been like this for over a year but the refrigerant is recent about a month. Do you recommend Red Angel plus more refrigerant? Or do I need a new compressor installed?
Reg-
Thank you for asking about your GMC Terrain. The best thing to do in a situation like this to get the high side and low side pressure readings. A lot of times, these pressure readings will point you in the right direction as to what is causing the problem. Based on your description, you could have a couple of different issues. The blower fan issue could be related to the lack of coolness as well.
Thank you!
-BDP
my 1992 ford f250 was blowing hot I recharged the system it was blowing cold went out a few hours later to drive it and go somewhere and it was blowing hot again so it does have a leak somewhere not sure were would the Red Angel A/C Stop Leak & Conditioner fix the leak or do I need to take it somewhere to see if it is my compressor that is bad it has been converted to the R134A I have used another bluedevil product with great success so would this fix my issue or no
Ted-
Thank you for asking about your Ford F-250. As long as you are not losing more than a pound of refrigerant a day, and the leak is not coming from the compressor, you would be a good candidate for the Red Angel A/C Refrigerant Stop Leak. Be sure to evacuate the system so that there is enough room in the system to add the product. You would Add refrigerant once complete.
Thank you!
-BDP
Hi! I bought a Volvo S60 2004 over the weekend. I was told the AC works intermittently, but there were no mechanical issues. After trouble shooting for a little while, I figured out that possibly adding more refrigerant was the solution. Before adding refrigerant, the AC would work for about 5-10 minutes before blowing warm and then eventually hot. After adding refrigerant, it blows ice cold on startup and then slowly fades to a lukewarm/warm temperature. Do I need to add more refrigerant (I added a $20 bottle from Walmart earlier today), or is there a more serious problem? Any advice would be great. Thanks!
Kal-
Thank you for asking about your Volvo S60. Based on your description, the best place to star would be to check the refrigerant level with a gauge. You wouldn’t want to just continue to add refrigerant if the system is not low. Adding too much refrigerant, or overcharging the system, could result in flooding the evaporator and damaging the compressor. If the A/C is blowing cold intermittently, the system being overcharged could be the cause, although typically it would be attributed to the evaporator freezing up because the evaporator drain is blocked. Try checking for blockages and that the cabin air filter isn’t plugged.
Thank you!
-BDP
I have a ‘75 Monte Carlo that uses R-12 and blows hot. Assuming I have a leak somewhere, can I use Red Angel to detect/repair? Are the proper fittings supplied with the kit to inject the dye on this vintage car? I have R-12 Freon to add to the system.
Tom-
Yes, the Red Angel A/C Stop Leak is safe and compatible to use on your Monte Carlo. When using the Red Angel (Part #49496), you would also need the oil injector to add the product. The Oil Injector can be found here on our website: (https://gobdp.com/product/oil-injector/)
Thank you!
-BDP
I have a Buick Encore 2016 and I noticed a small leak of a bright green liquid, a mecanic said is probably a leak from my a/c compressor. Any suggestions
Elba-
Thank you for asking about your Buick Encore. Have you noticed any issues with the A/C? Bright green liquid could also be antifreeze leaking out. If you are unsure as to what is leaking, it may be best to bring the vehicle to the mechanic for a proper diagnosis.
Thank you!
-BDP
Hello!
We’ve added two bottles of Red Angel to our van’s A/C system and it still leaks. We have a ‘94 Ford e-350 with the 5.7L. Granted, the first time the leak WAS the compressor. We have since replaced said compressor with a genuine Motorcraft one. We’ve also replaced the orifice, evaporator, condenser and accumulator and the high side port and run Red Angel through the system and over a couple of days the pressure in the system returns to 0. Note: we live in Central Texas and when we have used Red Angel it has been during high temp (100+ degrees) days. On your site it mentions that it is a temperature difference that causes the chemical reaction resulting in the crystallization of Red Angel. So our question is: Does the temperature at which Red Angel is used affect its effectiveness? My dad used Red Angel in his old Dodge minivan and it worked spectacularly and a year later is still holding strong. We were hoping for similar results. 🙁
Many thanks in advance for your reply!
Noemi-
Ambient temperature really wouldn’t influence the product’s ability to seal, even in the higher temperatures you are experiencing. If the Red Angel was first used with a leaking compressor, the product’s ability to seal would have been completely compromised. Based on your description, it seems that you performed a second application after the compressor was replaced? Please contact our technical support line at 888-863-0426 so that we can get a little better understanding of the vehicle’s condition and be able to make any appropriate recommendations.
Thank you!
-BDP
My A/C has not worked in two years. I found a condenser leak 2 years ago and never did anything about it. Is it too late to try any DIY products? Would there be too much moisture in the system to try to charge it with store bought cans and using Red Devil to stop the leak? Thanks
Michael-
Typically, the longer you leave an issue/leak unattended, it could cause other parts/components to prematurely fail. Based on your description, it would be worth it to try and have the system evacuated to use the Red Angel A/C Refrigerant Stop Leak. As long as you aren’t losing more than a lb. of refrigerant per day, the product should be able to seal.
Thank you!
-BDP