Does An AC Stop Leak Sealer Actually Work?

Does AC Stop Leak Sealer Work

If you like to work on your car yourself and you know a little bit about cars, you must have come across leak sealants when buying accessories for your car.

Most people who haven’t used a leak sealant before will wonder if it really works, because the advertising for these sealants implies that these things are magic and will immediately seal AC leaks and other types of leaks in your car.

You get a low-cost product that will fix your car’s problems that would cost you several hundreds of dollars if you decided to have it checked and repaired by a mechanic.

This raises the question of the credibility and authenticity of these AC leak seals. Is it too good to be true, and could you do more harm than good by using these AC leak seals in your car? Let’s find out!

What is an AC leak sealer?

An AC leak sealer is a product that works by reacting to the temperature when the refrigerant is flowing out from a pinhole in the AC pipe. When reacting to the leak location’s temperature, it will become a hard sealer instead of a liquid, and therefore it will stop the leak.

Even if you may think so, AC leak sealers are not new on the market. In fact, these products have been widely used in the natural gas industry for many years. These compounds have long been used to seal small leaks in gas pipelines to save time and money for manual repair.

Chemical-based sealers consist of a thick liquid substance that reacts with temperature and water to form a sealant that looks like epoxy resin. There are also particle-based sealants that work differently from chemical-based sealants.

ac leak sealer

Do AC leak sealers work?

Most AC stop leak sealers work well to stop small pinhole leaks in the AC pipes, but I don’t recommend using one. It is not proven that they can stop leaks around O-rings or shaft seals, which are much more common than pinhole leaks in AC systems.

There are a lot of different opinions when it comes to AC leak sealing. Here are the advantages and disadvantages of using an AC leak sealant, so you can ask yourself if it is worth it.

In my opinion, it is much better, and also probably cheaper in the long run, to repair a leak properly.


  • They can repair minor AC leaks, like pinhole leaks.
  • It can save you a lot of money instead of replacing expensive parts in the coolant system
  • Can prevent further leaks
  • Cheap to purchase


  • They can clog the expansion valve, the AC evaporator/condenser as well as other parts. This can cause significant additional repair costs.
  • They can disturb the flow and pressure of the AC system. This can cause the efficiency to be reduced by up to 10%.
  • Large leaks cannot be repaired.
  • It is not proven that they can seal around O-rings and shaft seals, which are the most common leak places.
  • It is often more of a temporary solution than a permanent one because of the high pressure within the AC system.
  • If you visit a workshop and notice that a leak sealant is present in the AC system, the system must be flushed before. The additional costs of this are at least $100 or even more. If they do not know about the leak, it can damage their AC machine, costing over 5k dollars.

RELATED: How Much Does an AC Recharge Cost?

Is AC Stop Leak Sealers bad for the AC system?

Yes. AC stop leak sealers are bad for your AC system. They can clog important parts like the expansion valve, evaporator, or condenser. An AC stop leak sealer will also reduce the efficiency of your AC by up to 10%.

You must understand that AC stop leak sealers react to water, and when they do that, they become hard. This is why AC stop leak sealers seal small pinholes by reacting to the condensation caused by the temperature around the pinhole.

When you have an AC leak, not only will the AC refrigerant go out of the system, but water or condensation will also get in. As I told you before, the AC leak sealer reacts to water, so what happens when you pour the AC leak sealer into a system with water?

Exactly! It will cause it to harden inside the AC system, and this can happen in places like the expansion valve or the condenser, which can cause the AC system to stop working altogether. It will also often result in an expensive repair cost.

What is the best AC leak sealer?

If you still want to use an AC leak sealer in your car, the best AC leak sealer I would recommend is the Red Angel A/C leak sealer from Amazon. This is an affiliate link, and this means that at no cost to you, I may receive a small commission for qualifying purchases.

Remember that even if it says that it does not clog the AC system, it can still happen, and you need to be prepared for that. Also, remember that if you use this, you may end up with more expensive repair costs. I definitely recommend repairing the leak properly instead.

The different types of AC leak sealers

There are actually two different types of AC leak sealers that you can use, and both of them have their own pros and cons. Here are the two most common types of AC leak sealers:

1. Powder/grain-based sealers

The first the powder or grain type – is a sealant that contains tiny particles inside the compound. This particle-based sealant works by plugging the leak or cavity with its tiny particles and forming a fine sealant. The tiny particles sit together inside your refrigerant line.

There is a big risk that this kind of AC leak sealer will clog your AC system, so I do not recommend it. In addition, these types of AC leak seals are getting older and older, so you will probably find chemical-based AC leak sealants in most cases.

2. Chemical-based sealers

The second type of AC leak sealers, containing a chemical compound, is now more common on the market. They exist under different names and brands, but their purpose is the same. Their purpose is to seal the leak so that the refrigerant does not escape.

These chemical-based seals seem to be safer than the first type, because these seals do not really block the leak, but rather form a tight layer over it to prevent the gas from escaping.

These chemical-based compounds can be supplied in a single bottle, as we have already discussed, or in two bottles, with the sealant and conditioner in separate containers.

Where do most AC leaks occur?

The most common location for an AC leak is the condenser as it is mounted in an exposed area in front of the car. Other areas where leakage can occur are the compressor, the lines running from the compressor to the condenser and at fittings and connections.

Should I use an AC leak sealer?

If you have a newer car you care about, I do not recommend using an AC leak sealer. One potential problem is that the AC leak sealant can clog up your car’s AC system. This can lead to decreased efficiency and potential AC system damage.

How long does AC Stop Leak last?

Most AC stop leak sealers are advertised as permanent leak sealants. However, most stop leak sealers will last for around a year before needing to be replaced, depending on the make and model of your car, the severity of the leak, and how often you use your AC.

How much does AC Stop Leak cost?

The cost of AC Stop Leak will vary depending on the size of the bottle and where you purchase it from. A small bottle can typically be found for around $20, while a large bottle can cost upwards of $40. You can often find AC Stop Leak at auto parts stores or online retailers.

Categories: Air condition

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