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Automotive Air Conditioning Leak Sealer

This article courtesy Cool Profits Magazine
This is an updated version of an article which first appeared in Cool Profits Magazine. It has been reprinted here with permission from the author.


Dr. Jekyll or Mr. Hyde to the system?

Right now you may be asking yourself what's an article about A/C "stop leak" doing in a nice, professional trade magazine like this? Two reasons: 1) along with amateurs, shade trees and ne'er-do-wells, actual professional air conditioning technicians worldwide are using these products, and 2) in the spirit of Fox News' very popular "fair and balanced" reporting style: "we report, you decide."

As controversial as alternative refrigerants are…
I've watched the progress of this product after seeing it pop up on the bulletin board at Naturally, most of the first comments, from professional A/C technicians, were non-complimentary at best. Then a few more adventurous souls chose to test the product. Soon most everyone was at least interested in the outcome.

Part 1, from the vendors
To research this article we asked several service techs to tell us what they wanted to know about A/C system sealers. Those questions, along with a few of mine, were then posed to the four manufacturers of the product that I could find. Their answers are below.

Part 2, in the next edition, will be for comments from you, the A/C technician. We'd like to hear of your experiences, both successes and failures.

1. How does your sealer actually seal an A/C system?

From SSR/Cryo-Chem: The Cryo Seal (or sealant) product reacts with air and moisture in the air (humidity) to form a solid, polysiloxane (epoxy) seal at the site of the leak.

From Cliplight Manufacturing: Super Seal Pro™ is a blend of chemicals designed to seal leaks in both the metal and rubber parts of an air conditioner. The chemicals contain a formulation that is activated by extreme concentrations of moisture to solidify and form a permanent patch. As refrigerant leaks out of the system, moisture is created and activates the chemicals to self-seal.

Essentially, the extreme temperature differential at the leak point causes condensation. This "moisture" activates the chemical.

From Keep-it-Kool™: A/C System Sealer is a two part moisture cure polymer that circulates within the system as a liquid. At the point of a leak, the leaking refrigerant creates a small amount of moisture because of the pressure drop. That moisture causes the sealer to set and form a permanent seal.

From Technical Chemical: Castrol/Johnsen's Leak Stop incorporates an active ingredient that rejuvenates the seals, gaskets and o-rings in the A/C system.

2. Will it work with all (mobile) refrigerants?

Cliplight: Yes, except hermetically sealed compressors for which testing is underway.

Cryo-Chem: There are Cryo Kits for both R-12 and R-134a systems.

Keep-it-Kool: The Keep-it-Kool™ A/C System Sealer was developed and tested for use with R-12 and R-134a refrigerants.

Tech Chemical: Leak Stop is available for R-134a (#6536) and FREEZE 12 (#6002).

3. Will the material clog TXVs, FOTs, VOVs, Schraders, accumulators, driers or any other A/C components?

Cliplight: No, when the chemical blend is injected into the system, the drying agent removes any moisture present at the valve core.

Cryo-Chem: The "SSR Kit" is composed of two components: a can of Tune Air and a can of our Cryo Seal. The Tune Air chemical dryer reacts with moisture and converts it into silicon oil, which is inert to the system. Chemical drying achieves and maintains a zero parts per million moisture level within the system. This is the best preventative maintenance one can perform.

After replacing the dryer/accumulator, the Tune Air is added and the system is run for ten minutes. Only then does one add the Cryo Seal.

Keep-it-Kool: No, the sealer will not clog or effect any other component of the a/c system when installed according to manufacturer instructions.

Tech Chemical: No.

4. Will it harm any of the system components?

Cliplight: No. During the injection process, drying agents in the blend prevent any sealing activity.

: No, it will not harm any of the system components.

Tech Chemical: No.

5. Will it lessen the cooling performance of the system? (Increase system temps and pressures?)

Cryo-Chem: Just adding the Tune Air chemical will result in a 5 - 7° drop in duct temperature within 10 or less minutes of application.

Cliplight: It may improve cooling performance as it improves thermal efficiency.

Keep-it-Kool: All of our tests have indicated that there is no effect on the a/c system’s performance or ability to cool. There were no noticeable changes in pressures.

Tech Chemical: No.

6. What happens to the sealer while it is in the system?

Cliplight: The chemical formulation remains in the liquid state inside the a/c until it detects moisture at a leak point and then self-seals. It does not affect the lubrication ability of the system oil in any way.

Keep-it-Kool: The Sealer remains a liquid while in the system.

Tech Chemical: Nothing.

7. What types and sizes of leaks will it seal?

Cliplight: If the system is leaking slowly and holds a partial charge for at least two weeks, Super Seal Pro will seal the leak. It will also seal most medium sized leaks, where refrigerant is lost in less than two weeks. However, if the hole is large and the refrigerant charge is lost within 24 hours, the system will need manual repair.

Cryo-Chem: Because the chemical is reactive with moisture, it needs a completely dry system prior to installation. Consequently, we require the replacement of the receiver/dryer or accumulator, depending on system type.

The sealer is designed repair leaks in all "stationary" metal system components (leaking compressor shaft seals excluded). We also do not recommend using it on a known hose leak.

Accordingly, the first step to successful seal is to properly diagnose the problem and use the product only when appropriate. The one time when we do advocate its use on a potential hose leak is for the nagging, two or three week leak that the technician can not locate. It will be sealed despite the fact that replacement would have been the preferred repair technique.

Keep-it-Kool: The system must be pulled into vacuum and after 10 minutes, be able to hold at least 25" of vacuum for at least 5 minutes. This assures the installer that the leak (or combination of leaks) is small enough for the sealer to seal.

Tech Chemical: Typically, A/C system leaks will occur at mechanical joints (hose connections, flange connections, mechanical seals, etc.). These are the type of leaks that are sealed with Castrol/Johnsen's Leak Stop.

8. Will it seal multiple leaks?

Cliplight: There is enough material in a single application to seal multiple holes in both the metal and rubber parts of the air conditioning system.

Keep-it-Kool: Yes. Each of the kits includes enough material to seal several leaks.

Tech Chemical : Yes.

9. How long will the sealer remain in the system? (Will it degrade performance as time goes on?)

Cliplight: Our sealer forms a permanent repair when it comes into contact with moisture. If there are no leaks in the system, and therefore no moisture, it will remain liquid with the lubricant in the system, ready to seal any new leaks. It causes no degradation of performance.

Keep-it-Kool: The sealer will remain in the system until such time as the refrigerant is removed or recovered.

Tech Chemical: Indefinitely. The ingredients in Leak Stop will not degrade A/C system performance in any way.

10. What happens to the sealer if a line or component breaks catastrophically?

Cliplight: Along with refrigerant and lube oil, the Super Seal Pro material is blown out of the system.

Cryo-Chem: We do not introduce significant amounts of the Cryo-Seal chemical into the system in order to effectuate sealing. Much of the available active material is used during the leak sealing process. Whatever is left is a volatile (in that it readily vaporizes) chemical which tends to leave the system when the refrigerant is discharged.

Keep-it-Kool: The sealer would be expelled from the system with the oil charge.

Tech Chemical: Some of the Leak Stop ingredient may be lost since it travels with the lubricant in the system.

11. What happens to a "sealed" refrigerant when it is recycled? Will it screw up a recycler?

Cliplight: The sealer will be removed from the a/c system with the refrigerant, and then will be separated from the refrigerant with the reclaimed oil. No effect on the refrigerant.

Cryo-Chem: We are happy to report that we have not had a single reported incident of a system being reopened later and residual Cryo-Seal causing contamination of the system, regardless of whether it was flushed.

Keep-it-Kool: During refrigerant recovery or recycling, the sealer is removed with the oil.

Tech Chemical: Since Leak Stop travels with the lubricant in the A/C system, it is recovered and discarded with oil. Even if the active ingredient in the Leak Stop did make it all the way through the recycling unit, no damage would occur to any of the components in the recovery/recycling system.

12. Where did this technology come from? Is anyone outside of auto a/c using it?

Cliplight: The sealant technology in Super Seal Pro has been used for decades in the underground gas transfer industry, sealing leaks in pipes, tanks, compressors, and other gas filled containers.

Tech Chemical: The active ingredient in Leak Stop has been around for some time; uncertain as to its applications in other industries.

13. Is your product flammable, or does it cause a non-flammable refrigerant to become flammable?

Cliplight: No, it has a very high flashpoint.

Cryo-Chem: Our products are non-flammable and will not effect flammability of a refrigerant.

Keep-it-Kool : From our tests, the sealer causes no effect on the refrigerant.

Tech Chemical: No.

14. Cost to the shop, or suggested retail price?

Cliplight: Super Seal Pro will sell for approximately $45 US and $70 CDN.

Keep-it-Kool: Suggested Retail: $64.95.

Tech Chemical: Suggested retail is $4.50 per 4 oz. can (single application).

15. Suggested applications? Should it just be used for Hail Mary repairs, or is this something that has a greater potential?

Cliplight: It allows the garages to keep their 'older car' business when expensive parts replacement is not financially justifiable, ideal as a maintenance (whatever the year of the car) and as a perfect complement to our Retro Fit product for modifying R12 to R134a.

Cryo-Chem: We encourage the technician to attempt to sell the part first, before offering the sealer kit. When a customer is sticker-shocked into declining the job, the kit offers a logical alternative. However, we recommend that it always be offered as an alternative.

Keep-it-Kool: The sealer can provide an excellent alternative repair method. After all, when a shop quotes the full job and the customer can not afford to proceed, the shop is left without a sale and usually with any profit. Using the sealer as an alternative repair allows the shop to proceed with the job and make a profit.

Tech Chemical: After completing a large mechanical repair, a good practice would be to install the sealer as a safety precaution. Countless times a system is checked and the technician finds only one leak. Once that leak is repaired and the system charged and operating at normal temperatures, the next "weakest link" starts to leak. The customer complains that he can't afford to proceed with the repair of the second leak, and would not have proceeded to spend any money on the first repair if he knew this would happen. Therefore, the service shop has an unsatisfied customer.

16. Will it seal leaking compressor seals?

Cliplight : It will not work as a sealer on shaft seals as the rotating shaft pumps out material before it gets a chance to work its magic. It will seal compressor body gasket leaks.

Cryo-Chem: No.

Keep-it-Kool: The sealer will not work on what we refer to as "moving" leaks. That is leaks caused by compressor shaft seals or spring lock couplings that generally leak because of vibration.

Tech Chemical: Leak Stop will rejuvenate the rubber seals typically found in compressor shaft seals (rotating shaft seals) and/or compressor gaskets to help seal any leaks.

17. Most importantly: Will parts of the sealer solidify in the system (contact with moisture), float around and eventually plug up a TXV or FOT?

Cliplight: No, the concentration of moisture in the system is too insignificant to activate the product. (See 1, referring to extreme concentrations.)

Keep-it-Kool: There is a potential of the sealer attaching itself to a very wet desiccant bag. Our instructions advise that on old systems that may not have received ongoing service, a replacement accumulator or drier would be an advantage. We have found no indication of any particulate causing problems with the systems.

Tech Chemical: No.

18. If the desiccant in the accumulator or drier is holding water, will the sealer combine with that water, solidify, and then spread throughout the system?

Cliplight: Moisture in the dryer is not in enough of a concentrated form to activate the sealer. After using our sealer, dryers have been cut open in our lab and no evidence of any solids or product crystallization was found.

Cryo-Chem: Tune Air will not restore a wet, saturated dryer. It's designed to remove the last "free" moisture from the system and refrigerant oil. We require all dryers/accumulators to be replaced before adding our kit.

Keep-it-Kool: See answer to 17.

Tech Chemical: We recommend Castrol/Johnsen's Leak Stop not only as a solution for "phantom leaks" but also as a preventive maintenance measure to head off potential leaks in the future.

19. Is an MSDS available for your product?

Cliplight: Yes.

Cryo-Chem: Yes. Phone or written request.

Keep-it-Kool: Yes.

Tech Chemical: Yes. Contact our Customer Service Dept. at (800) 527-0885 for details.

20. Suppose a system has been treated with sealer but then is opened, and left open for a few days, in a high humidity area. The refrigerant is recovered but not all of the oil. Will the sealer that is in the remaining solidify because of the humidity and become a problem when the system is reassembled?

Cliplight : No. High humidity in a fully open system will not cause the sealer to activate. It takes a leak to generate the concentrated condensation.

Cryo-Chem: A wet dryer can deactivate the Cryo Seal and prevent it from ever reaching the leak site. See answer to #17.

Tech Chemical: No, it will not. Leak Stop rejuvenates the O-rings, seals and gaskets, it does not solidify in the A/C system.

Additional information submitted by the sealer vendors:

Cliplight: We've recently changed from a 2-step process (with separate applications) to a single container application to increase efficiency.

Super Seal Pro is vacuum packed which requires the technician to vacuum the system prior to installation. This ensures that the solution is completely drawn into the a/c system quickly and effortlessly. We believe that you cannot separate these steps, the 1-step process assures a high level of success.
Additionally, ours has a beefed up drying agent and an increased dosage of the ingredient that acts as a catalyst for the leak sealant (polymerization).

Cryo-Chem: SSR/Cryo-Chem has been marketing specialty chemical products for mobile air conditioning systems for over eighteen years. We have the advantage of field experience that has shown us how they will perform, and how to be successful in using and selling them to the public.

We are unique in the industry in that we offer a 1- year, unconditional warranty. The technician fills out a registration card with the vehicle type, age and mileage, as well as information about the servicing location and technician. By comparing the data on the returned cards to our known warranty rate, we have established a failure rate of 1 in 150 during our existence. Plus, we also learn why the product fails on certain applications.

While the vast majority of failures are due to misapplication or improper installation, we have experienced failures even with proper installation. On these occasions, we found that were "running seam cracks." Example: evaporator failure along the welded seam of the tank and coil header.

As the product seals along the leading edge of the leak, that pressure builds. The crack opens further, breaking off the seal. The only indication of this type evaporator failure is that a system, which is known to be leaking, holds vacuum for excessively long periods. Why? Because the crack draws closed under vacuum (but won't hold pressure). Thankfully, this type of leak is rare.

In the past several years, we have found that 1 of 6 cars reported are Mercedes. These vehicles have a high rate of evaporator failure, and about a 20+ labor-hour repair. Plus, removing the dashboard requires disconnecting the air bag system and other vehicle control/monitoring components. In this case, liability and comebacks tend to cause our Kit repair to be offered before the component replacement. We believe this situation with the Mercedes products to be indicative of the future of our place in the automotive air conditioning industry.

Keep-it-Kool: Our Sealer was developed for professional use.

1) A UV dye is included in the Sealer in the event that a leak it too large to seal.

2) We use a proprietary installation hose kit that allows the technician to: a) interrupt system without any loss of vacuum; b) complete the installation without leaks, the risk of contamination, or having the sealer set in the installation hose.

3) Our Sealer uses a proprietary patented packaging process that assures a completely dry, airless container. This provides the longest shelf life.

This is it for Part 1.

In the next article, we will hear from the technicians who have used the product. If you are one of those techs, and would like to contribute your findings, please email, call, write or fax Cool Profits Magazine

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