Healing the “Stop Leak” Reputation

Do you have an expensive leak in your automobile? Well, we know that sometimes fixing the hard part on your car just isn’t an option.  If it’s not in your budget or the car is simply not worth it, perhaps a chemical stop leak product is the answer!

canA new generation of stop leaks emerging in the marketplace is working hard to shed the old reputation of stop leaks as dangerous “snake oils” that do more harm than good. This includes an oil-based stop leak for mobile air conditioners (A/C) that reacts at the leak point only while lubricating and conditioning the system.

Accompanying the new style of A/C stop leak is a chemical sealant for cooling system leaks that does not use any harmful metallic filings or pellets to plug the leak. These new stop leaks are comparable to hard part repairs in a variety of ways at a fraction of the cost. The products provide permanent repairs for customers who cannot afford an expensive repair cost or for a vehicle in which the owner decides is no longer worth spending a lot of time and money. (For more information on cooling system stop leaks, please visit gobdp.com)

Air conditioning stop leaks have been a long-time enemy of service technicians and their recovery equipment, compressors and orifice tubes. With limited success at actually stopping leaks, early A/C sealers do far more harm than good by crystallizing throughout the system. These stop leaks react to moisture and oxygen at the leak point. The leak is moderately sealed, lasting at best for a few months. The danger of these sealants is that the remaining product continues to react with the moisture in the system. The most common place for moisture in the A/C system is the orifice tubes where condensation is ever present. This causes crystallization of the stop leak in these hoses, which eventually clogs the system. Furthermore, these crystals move into the compressor, causing it to fail within three to six months. Once the vehicle is brought in for service, an unsuspecting technician recovers the system immediately sucking these crystals in, contaminating the machine and rendering a $2,500- $5,000 piece of equipment useless. After reviewing this chronology of events, it is readily apparent how previous stop leaks got such a bad reputation.

The new oil-based stop leaks have a tough road ahead overcoming the negative connotations brought about by existing A/C stop leaks. However, this new era of sealant works in an entirely different fashion. Oil-based stop leaks are activated by pressure and flow velocity at the leak point. The oil acts as a lubricant and is compatible with the PAG or ester oil already present in the A/C system. The stop leak is inert when injected into the system through the low side port. The refrigerant charge activates the molecules in the sealant as it reacts to flow velocity at the leak point only.  The result is a flexible yet strong repair.

As long as the A/C system is not losing more than a pound of refrigerant per day, this repair is permanent. Once the leak is sealed, the remaining oil will continue to lubricate the system. Therefore, there is never any crystallization in the orifice tubes, no damaged compressors and, most importantly, if the system is ever recovered, the remaining stop leak is reclaimed with the oil, keeping the recovery machine safe and technicians happy.

Because this type of stop leak is safe for equipment, easy to use and compatible with a variety of refrigerants, its marketability is infinite. Service technicians can use it as preventive maintenance with almost any repair job. The oil will remain as an inert lubricant in the system waiting for a leak to present itself.

The amount of time and money saved repairing minor leaks results in larger profits and easier sales with a working air conditioner. Depending on the vehicle model, replacing a compressor or evaporator can cost anywhere from $600 to $2,000. There are a lot of vehicles on the road that are not worth that much and a lot of people who can’t afford the expensive repair. Repair facilities can develop lasting relationships with customers by helping them save money when the hard part repair is not an option, while still making a profit on the system recovery and new charge. Positive word of mouth will spread, creating new business for the shops offering the oil-based stop leak as a treatment option.

The product takes less than 15 minutes to circulate through the system, sealing any leaks. It’s compatibility with a variety of refrigerants also separates itself from its predecessors. This new type of stop leak is compatible with R-134a, R-12 and R-22, as well as newer environmentally safe refrigerants. This compatibility will open the market beyond the automotive industry into home A/C applications as well. The potential for this new air conditioning stop leak is boundless because of its safety, ease of use and compatibility with a variety of vehicles and equipment.  For more information on available “Stop Leak” products, please visit Gobluedevil.com.

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64 responses to “Healing the “Stop Leak” Reputation

  1. With the compressor not kicking on do I need to add some refrigerate first then the stop leak or does it matter.

      1. I don’t understand the response you gave to Andrew. If the compressor is not running, how will the Stop Leak seal the leak before adding refrigerant? My logic wants to say add a small amount of refrigerant first to get the compressor to come on, THEN add the Stop Leak and let it circulate, and then finally recharge the system to spec. Am I wrong?

        1. Sara,

          Thanks for your question. Your logic is correct in that you need enough pressure in your system to get the compressor to engage. Most often, small leaks don’t leave your system completely empty and the pressure added by the Red Angel AC Stop Leak Aerosol is enough to allow the system to restart. If that isn’t the case then you would need to add refrigerant until the pressure is high enough for the compressor to cycle.

          Thanks again for your question!
          -BD Auto Pro

    1. Yes, you need some pressure in the system to activate the compressor clutch which pumps the product into the system or you can jump the connector out to engage the clutch. Either way you will still have to fill the system with R134 for the stop leak to work.
      Put enough in to activate the compressor then top the system off so you don’t over fill.
      It actually is a good idea to jump the clutch connection first to make sure it is not the problem.

    1. Karan-

      The Red Angel A/C Stop Leak has a quick connect hose that will attach directly to the low side service port. After removing the tab from the can you may connect the coupler to the low side service port, with the engine on and A/C set to max, and depress the button on the top of the can to inject the Red Angel. After the full contents of the can are released you may recharge the A/C system with the proper amount of R-134a.

      Feel free to contact our tech support team at 888-863-0426 for any further instruction.

      Thank You!


  2. am losing 2 to 3 oz. of Freon every 7 to 8 days. I had garage mechanic put in a can of blue devil ac stop leak. we cannot find the leak using a sniffer and the dye/glasses to see it if there is a spotted leak. the ac stop leak did not stop the leak. will another can be advised?is it worth the second try?
    suggestions and/or advice would be appreciated as this tiny leak has been a mytery to us for quite a while;
    I forgot….,the subject ac is on a well kept 1995 chevy lumina. lou pippen

    1. Lou-

      Please contact our technical support line at 888-863-0426 so that we can get a better understanding of the leak you are experiencing and make a recommendation based on the results of using the Red Angel A/C Stop Leak & Conditioner.

      Thank you!


    1. Palmer-

      Yes, the Red Angel A/C Stop Leak will stop a leak from the evaporator. It will work on just about any type of leak within the A/C System as long as it is not related to the compressor.



  3. Hello BDP,
    I came across an advertisement for your A/C Stop Leak product…
    I have a 2001 Chrysler PT Cruiser I recently had the compressor, receiver drier, hoses and o-rings.
    My mechanic stated the the only thing left was the evaporator core unit and that required the complete removal of the dash down to the firewall to obtain access… and his quote for the labor alone was $1500.
    I declined to have the work done… Being a commercial aircraft mechanic I decided to try and tackle the job of replacing the evaporator myself. I took as much of the dash apart as I could and ran into a road block where I could not find any other parts to remove to gain further access to the evaporator… I think the dang thing was welded in place. Long story short – I put the car back together and am stuck with a non operative A/C which sucks big time as I live in south Florida… I am considering giving BDP A/C stop leak a try… I’m trying to determine whether to use the aerosol or the liquid, I’m leaning towards the aerosol as I don’t have the equipment to use the liquid.


    1. Charles,

      Thanks for your question about your PT Cruiser. Replacing the evaporator in almost any care is a significant project, but especially so in yours so do not be discouraged with your project. We would also recommend using the BlueDevil Red Angel AC Stop Leak aerosol as it is easy to use and doesn’t require special tools. The liquid and injector are designed more for garages who will be repairing multiple vehicles. If you have a leak in your evaporator BlueDevil Red Angel AC Stop Leak will seal the leak, then you can recharge your system and get back to having cool air.

      Thanks again for your question!
      -BD Auto pro

  4. I have a pretty large leak that developed in the condenser unit. it leaks out as i’m trying to fill the system. Will the
    Red Angel AC sealant work on this type of condenser leak?

    1. Mark-

      Based on your description, you may be losing refrigerant a little too quickly for the product. A system that won’t hold 5 inches of vacuum on the low side for 25 minutes has a leak that is too large to be sealed, and may require a hard part repair.

      Thank you!


  5. I replaced the air compressor, orifice tube and A/C Accumulator/Receiver Drier on my 2004 Ford E-250. I have a slow leak, takes months for it to lose all Freon. I currently charged the system. Can I add stop leak to it now? Or do I need to evacuate, vacuum and recharge it again? Thanks.

  6. Just charged my 82 Mercedes 300 CD, and it blue cold for a couple days, but now only warm air. should the Red Angel be tried, in this situation?

  7. Does the system have to be completely empty to use? I recharged about 2 days ago… would it be ok to use or should i let some more freon leak out?


    1. Chris-

      Thank you for asking about the Red Angel A/C Stop Leak & Conditioner. The system should be evacuated or partially depleted to properly install the product. Feel free to contact our technical support line at 888-863-0426 with any other questions.

      Thank you!


  8. My 02 GMC Sierra was diagnosed with a coil leak 2 years ago when the AC first stopped working. No way to tell if the dye showed up there without ripping dash apart $700.00 bucks so I just dealt without AC. My question is after two years should I evacuate the system before trying this product and also will I need to partially charge system to get compressor to start before adding stop leak and then top off with more refrigerant after adding the stop leak?

    1. Gregg-

      You should add Red Angel A/C Stop Leak first and then recharge the system with the proper amount of refrigerant. Next you should allow the A/C to run on the maximum setting for 15 – 20 minuted to allow Red Angel to circulate.

      Thank you!


  9. One more question after using red devil can I charge the system the AC PRO coolant recharge can or must it be straight R 134? AC pro also has sealers are they compatible?

  10. I have a 2005 Saturn Vue. It has been diagnosed with a leak in the compressor. Will red angel stop leak work for that.

    1. Bill-

      Thank you for asking about your Saturn Vue. Unfortunately, the Red Angel A/C Stop Leak is not recommended for compressor leaks. A hard part repair may be your best option.

      Thank you!


  11. I have a Toyota Corolla 1996. Last year I filled the A/C with Freon and it lasted until the end of summer. This year I did the same but it only lasted a few days. I went to a garage and the mechanic checked the system for leaks. He found no leaks under the hood and told me that the leak must be inside the car. He has to take the dashboard off and fix whatever doesn’t work (probably the evaporator or condenser?). He told me that the job may cost up to $800-900. I came across your product, BlueDevil Red Angel AC Stop Leak aerosol and I wonder if this may fix the problem. Should I go back and ask him to try this Red Angel product? What do you think?

    Thank you

    Henry B.

    1. Henry-

      Thank you for asking about your Toyota Corolla. Based on your description, we recommend using the Red Angel A/C Stop Leak & Conditioner. As long as you are not losing refrigerant too quickly, you would be a good candidate for the product. Feel free to contact our technical support team at 888-863-0426 with any other questions.

      Thank you!


      1. It’s been a month and 1/2 since I used the Step Leak Red Angel and my air conditioner is still working well. It looks to me like this product does as promised.

        Thank you


    1. Ismael-

      Unfortunately, we do not recommend using Red Angel in vehicles that have an electrically driven compressor. Hybrid vehicles use electrically driven compressors which require very specific conductive oil.

      Thank you!


      1. Why doesn’t the can say “not for hybrid electric driven systems” like every other stop leak product on the market? Your website states it is compatible with all PAG and Ester oils, it’s my understanding nd 11 is an Ester oil. I just used your product in my 2006 prius based on what I’d read on your website and your lack of the “standard hybrid” on the can. I hope my car is ok and your over sight in labeling is not market driven !!

        1. Rusty-

          Our current labeling does state “not for use in electrically driven compressor systems”. It sounds like you may have purchased a can that was manufactured years back and had old labeling. Literally the only oil that is compatible with electrically driven compressors is ND-11. The owner’s manual for the Prius specifically states “CAUTION: Use only ND11 type compressor oil”. ND-11 oil provides high dielectric properties, which help maintain the integrity of the compressor’s electrical windings.

          To be on the safe side, we recommend that the A/C system is evacuated and recharged.

          Thank you!


  12. My AC evaporator is leaking in my 2000 Cherokee classic and it takes several days before I realize that it is no longer cooling. Would that be considered partially evacuated at that point so I can try your product?

    1. Jeremy-

      Yes, it would be safe to add Red Angel A/C Stop Leak at this point. The system is definitely partially depleted if it is no longer cooling properly. After injecting Red Angel you will want to add the proper amount of R-134a to recharge the A/C system.

      Thank you!


  13. I have a car with r12 how do I add your ac stop leak to this system since the r12 product does not come with a hose attached

    1. Ed-

      You would need an oil injector to properly add the BlueDevil A/C Stop Leak. We do not manufacture an oil injector for R-12 systems but, one could be purchased from your local parts store.

      Thank you!


  14. Will this product repair a 2001 Chrysler 300M permanitley or temporary ? And is it available in Canada, does it have any guarantees of any kind not to damage any part of the A/C unit ?

    1. Linda-

      Thank you for your interest in the Red Angel A/C Stop Leak! Once the product seals, it would be a permanent seal. It is currently not available in Canada, however, you can order the product directly on our website at, http://store.gobdp.com/a-c-stop-leak-aerosol-00222/ . The product does not contain any solid or particulate matter that will clog the A/C system or harm the recovery unit. Feel free to contact our technical support line at 888-863-0426 with any other questions.

      Thank you!


  15. I have a ’78 Lincoln Mark V 460. 21K miles. It is a show car, so don’t really want to convert it unless absolutely necessary. AC compressor seized and was replaced about 10 years ago. About 5-6 years ago, was leaking R12, my mechanic used dye, foudn a leak, replaced the evaporator O-ring. Charged it up, within a week was blowing warm again (haven’ tbeen back to him since). Currently even with car idling the hose from radiator side to firewall gets icy, but air inside the car is not cold. So I think that means it coudl be low on R12. I suspect htere is still a leak somewhere. About to take it in next week to a different mechanic for leak testing. If he can’t fix it I may give this Red Angel A/C Stop Leak a try. It sounds like it should be compatible with my old R-12 system. Does it come with the necessary valves to attach to my R-12 low-pressure fitting?

    1. Tim-

      Thank you for asking about your Lincoln. You would need an oil injector in order to properly add the Red Angel A/C Stop Leak. Based on your description, it does not sound like you are losing refrigerant too quickly, so you would be a great candidate for the product.

      Thank you!


  16. Used your product and unit has never blown this much cold air before.It has been 2.5 months and now is not working as well.I live in Florida and this has been a super hot summer.Should I add another can then add Freon or just Freon to see what happens.Mechanic says leak is in evaporator at firewall

  17. I have a 1994 Toyota Land Cruiser and live at 5600 feet in Arizona. 4 months out of the year its pretty hot. In mid June when things got pretty hot I noticed the air was not cooling as well. So I put a can of R134a in. Now its early September and I’ve noticed a significant decrease in cooling. It still cools, but we’re only in the high 80’s and it doesn’t really get cold on high like it should. My questions are: 1. Should I just let it leak out and start fresh in May or recharge now? 2. Which of your products should I use?

  18. Can this Blue Devil stop leak be used in a system charged with HC12 (propane/isobutane blend) such as Envirosafe 134?

  19. Hi ,
    I have a 2010 Mercedes B200 with only 29000Kms on the clock , I had my mechanic re gas it the first week of January , only to feel the hot air coming through here in Sydneys Summer the last week of February , so lasted approx 6 weeks. They checked it the other day, and found a leak on a coupling between the rubber tube and metal tube underneath .
    To replace the tube throughout is $400 odd just for the pipe and tubing , then ;labout so up to $900 time its all done .
    I said to him is there not anything that can seal that small coupling leak and he said no , not that he had heard of .
    Do you think your product would work here as sounds like it would reading the other comments here

  20. Hello there, I have a 2005 Prius with an extremely small leak in the evaporator (takes about a month for the ac to stop blowing cold.) I understand that it’s not recommended to use red devil in hybrid vehicles because of the lack of compatibility with oils for electrically driven compressors. My question is: will using red devil in a hybrid DEFINTELY kill the compressor? Without a doubt?

    1. Angelo-

      Unfortunately, we do not recommend using the product in your Prius as you should not use Red Angel in electrically driven compressors. Using anything but the recommended oil would compromise the system.

      Thank you!


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