Top 6 Head Gasket Sealants To Prevent Leaks

Last Updated on February 1, 2024 by John Robinson

Is your car showing some aging symptoms? If it’s a blown gasket, you should not ignore the warning signs. You might be thinking: Oh, no, not another expense. But driving your car as if there’s nothing wrong may even turn out to be more expensive.

You should pay attention to the problem with a fast-acting solution. And in this case, we’ve got your back.

If you don’t want to get a new head gasket job, you may want to check out the best gasket sealer choices we have rounded up:

Table of Contents

Best Head Gasket Sealers

1. BlueDevil Head Gasket Sealer

Best OverallBest Head Gasket Sealer

If you’re after a permanent and professional-grade solution to leakage problems, you may want to try the Head Gasket Sealer by BlueDevil. It works on either gasoline or diesel engines. It gets the job done where internal issues are concerned. These apply not only to the head gasket but also to the heater core, freeze plugs, and other coolant-related parts, except for the radiator core.

No matter how many cylinders your engine has or what material your head gasket is made of, this product can help in coolant leak repair. It can help fix any warps or cracks. It bonds with various materials, such as alloy, aluminum, plastic, cast iron, and multiple types of metals. And don’t worry, there’s no chemical in here that can harm your engine.

Once you pour the mixture, it can start the work of keeping overheating at bay. This little devil will be more effective if you use it with fresh coolant. After that, it can repair the issue permanently and increase your mileage. Your head gasket can remain on top performance, and your car can run great again.

Over time, however, the sealant may leave deposits that can clog pipes and passages, possibly a byproduct of its reaction to the heat in the combustion chamber. For a more optimal result, read and follow the instructions carefully. That makes it pretty safe and easy to use.

You can get one bottle for just around $20, which gives you enough value for your money. It is an exceptional alternative to having your engine repaired by the pros.

BlueDevil Head Gasket Sealer is Suitable For:

This sealant works well for both gas and diesel engines, no matter how many cylinders are there. It’s one of the best alternatives to having the pros repair your engine parts. It’s pretty affordable and safe to use. And it can keep your car’s head gasket leak-free for a long time.


  • It applies to a variety of materials, such as alloy, cast iron, plastic, and steel.
  • It can fix leaks, warps, and cracks to improve the engine’s performance.
  • It is professional-grade yet affordable.


  • It can react with the heat in the chamber, which may leave a deposit buildup.
  • It can also affect the performance of the thermostat.
  • It should always be used with fresh coolant.
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2. Bar’s Leaks Permanent Head Gasket Fix

Best Overall Runner-UpBar's Leaks Permanent Head Gasket Fix

This offering from Bar’s Leak suggests fast action. Will a quick fix have a long-lasting effect in this case? The 1111 Block Seal Permanent head gasket solution seems to prove it. After applying this sealant, you need to wait for only 15 minutes to see the results. You can pick up this bottle and rescue your car ASAP.

Further, this product will stop leaks without draining. If you’re dealing with a blown head gasket, it can get the job done as well. Seal the cracks in your cylinder and/or blocks if these are causing your car to stay idle in your garage. 

Its permanent sealing effect comes from the combined “antifreeze compatible sodium silicate sealing liquid and various size gasket sealing particles.” These components allow for the mixture to harden through the cracks and gaps of the auto parts. Given all these features, this hardworking product is a steal for its very cheap price.

Lastly, it is compatible with both gas and diesel engines. Follow the recommended amount during application to achieve optimal results. Use one bottle for 1.5 to 4 gallons cooling systems and half bottle for 1 to 1.5 gallons cooling systems. At 25 ounces, this one has slightly more content than BlueDevil.

This head gasket sealant is manufactured by a U.S.-based company, Bar’s Leak, which has been providing customers with its patented creations since 1947. It focuses on creating affordable, yet quality stop-leak products. The money-back-guarantee feature shows how confident it is with its offerings.

Bar’s Leaks Permanent Head Gasket Fix is Suitable For:

This product is great for both diesel and gasoline engines. It can also be the sealant of choice for people who want a quick-acting yet permanent solution to their gasket issues. With its bulk buying-friendly price, it seems ideal for individuals on a budget.


  • It acts as fast as 15 minutes while requiring no flush.
  • Its components can fill the tiny cracks in the cylinder and block, sealing the leak effectively.
  • It has an affordable price, making it perfect for bulk buying.


  • You should follow the directions carefully to ensure you’ll get your desired effects.
  • It may affect the performance of your thermostat.
  • It can leave a powdery residue behind.
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3. Steel Seal Blown Head Gasket Sealer

Best ValueSteel Seal Blown Head Gasket Sealer

Steel Seal designed a head gasket that fits the requirements of an engine with 8 cylinders. The Steel Seal Blown pour and go solution is not exactly the cheapest option, but it’s less expensive than spending a lot on professional mechanic services. So, what makes this the Best Value choice?

At around $200, this product weighs 160 ounces, almost eight times more than the #1 pick. The cost does not veer away from the bulk prices of the previous two items. Sourcing this one is also easy as it is available in many shops for automotive repair. Steel Seal, after all, is popular in these places.

During the application of the mixture, it will work to fill cracked areas and fix blown or broken parts. This is not limited to the head gasket. It can repair heater cores and freeze plugs. However, the manufacturer does not let you think it will perform for 100% of its users. Put it at around 95% instead.

Don’t fret, though, as using this is a no-brainer and most users find it effective.

Nevertheless, the company matches its honesty with a no-fuss, refund guarantee policy. It will accept reasons such as the product did not work after observing it, initially, within an hour of application, and even afterward. You won’t need to fill out forms and such. Just call technical support for the refund.

If the product works at the beginning and then ceases to do so, you can also receive a one-time replacement from the brand.

Steel Seal Blown Head Gasket Fix Repair Sealer is Suitable For:

This high-end head gasket seal fits the requirements of 8-cylinder engines. If you value honesty, you may also like the money-back guarantee provided by the manufacturer. It says that the product may work for only 95% of users.


  • The $200 price tag actually applies to a 160-pound bottle of this product.
  • It works within the first hour of application, fixing cracked and blown-out gaskets.
  • The no-fuss, money-back guarantee reassures buyers.


  • As admitted by the company, the sealant may work for 95% of users.
  • It may leave a buildup in your cooling system.
  • It may not be compatible with antifreeze.
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4. K-Seal Ultimate Permanent Head Gasket Repair

Best Value Runner-UpK-Seal Ultimate Permanent Head Gasket Repair

Seal a leaking spot or repair a crack permanently with the K-Seal Ultimate Permanent Head Gasket Repair. This pour-and-go product lets the affected area get fixed for good. Think about it: you won’t have to worry about that part causing problems ever again.

Is it too good to be true? Some owners of cars, SUVs (sports utility vehicles), and small trucks can attest that it delivers on its promise. Old or new, your car can benefit from this one. It does not only produce quick results, it also allows for a reliable sealing method. Both efficient and effective, this one offers value for your money.

On top of its quality performance, this head gasket sealer is safe to use. It is compatible with antifreeze or coolant. Also, it does not require its contents to be drained from the cooling system. That’s one less thing for you to worry about. Just make sure to shake the bottle well before application.

This K-Seal option was scientifically tested using the equipment at Brighton University. It also met the standards of ASTM D3147, which screens stop-leak additives. You get all these features for only around $20. It also comes with a Technical Specification Guide in case you need to do some troubleshooting during application.

It may not work on a Nissan Altima. If you have a big vehicle, try using two bottles instead. As a long-term stop-leak product, this one from K-Seal is the runner-up to the Steel Seal variant when it comes to value for money.

K-Seal Ultimate Permanent Head Gasket Repair is Suitable For:

To those who are seeking a long-term solution to gasket leaks, this product has a lot to offer. It is compatible with your cars, SUVs, small trucks, and large vehicles, whether they are old or new.


  • It permanently seals the spot where leakage occurred.
  • It can work for small trucks, cars, and SUVs.
  • It is pretty inexpensive, so many customers can access it.


  • It may not work on Nissan Altima models.
  • It can fail to work, so the company reminds users to read the guide.
  • It is still not a full fix.
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5. Permatex The Right Stuff Gasket Maker

Best BudgetPermatex The Right Stuff Gasket Maker

Here is another product from a known maker in the automobile repair and maintenance industry. The Right Stuff Gasket Maker is a one-minute solution for vehicles that use engines with closely spaced bolt patterns, usually import vehicles. Even with its handy size, it can work under high torque loads.

It is enough to cover two to three large gaskets. To fix leaks or resist blowouts, it creates an elastic rubber that seals the gasket. Oil, coolants, and ATFs (automatic transmission fluids) cannot damage this material. It can withstand extreme temperatures of up to 450°F (232°C) for continuous and 500°F (260°C) for intermittent.

The product can stop leaks caused by different factors inside your vehicle, whether it’s the vibration or thermal expansion. No additional tool is needed when you deal with issues in gaskets, oil pans, gearbox covers, valve covers, water pumps, etc. And it will take a single application to work.

Wait for a couple of hours (ideally four) for the formula to dry up. Its effects are long-lasting. However, use this only on gasoline engines. Make sure to follow the instructions on how to dispense it. This should help extend the shelf life of the product as it is suitable for multiple uses.

This stuff is also available in an array of sizes, including the PowerBead pressurized can, 5-ounce cartridge, and 11-ounce cartridge. The smallest you can get has 3 ounces, and (the link to which is shared here) costs around $15. You can buy according to your priorities and budget. But as we said, a little goes a long way with this one.

Permatex The Right Stuff Gasket Maker is Suitable For:

A single application of this gasket sealer should be used only on gas engines. In particular, it works on engines with closely spaced bolt patterns, such as the ones found in import vehicles. The various sizes also match different budget types.


  • It requires a small amount to seal leaks and fix gaskets effectively.
  • It creates an elastic rubber seal for the head gasket.
  • It also works on other auto parts, including the valve cover and water pump.
  • It comes in different sizes and prices to match your needs.


  • It does not work on head gaskets found in diesel engines.
  • The lever that controls the flow does not work optimally.
  • The pressurized can version may be hard to apply.
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6. K&W Head Gasket and Block Repair

Best Budget Runner-UpK&W Head Gasket and Block Repair

Since 1938, K&W has been providing do-it-yourself leak solutions to automotive owners and mechanics. Its products are proven to be good alternatives to spending thousands of dollars on professional car repair and maintenance. The K&W Head Gasket and Block Repair is one of these offerings. So, how does this sealant actually fare in the DIY leak-stop department?

This block seal features formulated using nanotechnology so that it can deal with blown-out gaskets in many kinds of vehicles, such as buses and trucks. It has multiple functions when applied. It is not only for head gaskets but also for engine blocks, cylinder heads, cooling systems, heater cores, and freeze plugs. It is compatible with radiators as well.

How does it work? Like any pour-and-go mixture, you apply this on the cracks. Let it harden and create a strong bond with the auto part material, allowing for permanent sealing. This can help take away your worries about a blown-out head gasket. The good thing about this product is it does not affect your car’s internal system.

This product is super effective, but it has an active chemical component. This may be harmful to the user. So always practice precaution when you are using it. You must also drain your cooling system and keep it from mixing with antifreeze during application.

A standard-size bottle weighs 35 ounces, and its price is pretty affordable for its size. Some users say that a bottle is enough for a 4-cylinder engine. You may need to use two bottles on an 8-cylinder engine.

K&W Head Gasket and Block Repair is Suitable For:

This sealant can be applied to many kinds of automobiles, including buses and trucks. One bottle can cover 4-cylinder engines. You may have to double the dosage for 8-cylinder engines. It should be used with care by DIY-ers because of the strong chemical component.


  • It can permanently seal cracks, so you won’t have to worry about gasket blow-outs.
  • It works on many kinds of automobiles, including buses and trucks.
  • It is an affordable sealant for DIY-ers who want an alternative to a visit to the pros.


  • It contains strong chemicals, so it has to be handled with utmost care.
  • The steps may be cumbersome for some people.
  • It may not work for all users.
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What is a Head Gasket?

New car owners or buyers may not be sure what a head gasket is and what it does. If you belong to this group, this section is especially for you.

A head gasket is an essential component of your car’s engine. It sits between the cylinder head (or just head) and the engine block (also called the cylinder block or just block).

What is a Head Gasket

Sealing in the engine’s combustion process, a gasket is geared up for an enormous task. Foremost, it contains the combustion process within the engine block. It also keeps the oil and coolant separate while the two fluids flow from the block to the head. To function optimally, it should be temperature-resistant.

When you need to buy a new head gasket, know about its different types and which one to get for your vehicle. You can choose based on the material used, starting from the most common:

  • Carbon This material has excellent sealing performance even on the worst flange surfaces. It can withstand long-term exposure to high temperatures.
  • Composite head gaskets Usually derived from asbestos or graphite, composites are a versatile material. They conform to the impurities of sealing surfaces. However, this old-generation gasket type is rarely used these days due to its tendency to blow out and asbestos-related health concerns.
  • Copper This metal is preferred for its high conductivity, durability, and conformability. Copper distributes heat evenly, making it resistant to warping. It also conforms to rough sealing surfaces, resulting in a tighter seal and a longer lifespan.
  • Graphite – With a softer quality, graphite can work well on an uneven surface and allow for more gasket movement. Graphite gaskets can withstand extreme temperatures, making them less prone to overheating.
  • MLS or Multi-Layered Steel Head Gaskets – Multiple stainless steel sheets typically make up MLS gaskets. Steel is preferred in modern gasket models due to its rigid nature, which defies distortion under extreme circumstances. It’s also one of your top bets for compressibility and heat resistance.
  • Rubber – This flexible material can survive extreme heat. It can be used in one-piece constructions or as a coating for gasket cores, including neoprene, to create a tight seal.

What are the Top 5 Symptoms of a Blown Head Gasket?

Blown head gaskets can be the cause of the following events. Make sure to check your engine with caution and care when you experience any of these:

Overheating Engine

One thing can lead to another, resulting in an engine that overheats. But when it does, it can cause head gasket failure. When this symptom occurs, you may want to look further into the root of the problem.

It could be a leak in the coolant or blockage in the radiator. For instance, coolant can leak into the cylinders, creating steam that can, in turn, heat up the engine.

Ignoring the overheating issue can also warp a cylinder head, especially if it’s made of alloy. Or the steam can damage the catalytic converter.

External Leakage

The head gasket that separates the fuel or coolant path from the outer side of the engine may break down. This can be signified by a fuel or coolant leak, which can create a mess and should be taken seriously. Although this isn’t the worst possible situation you need to prepare for.

You may want to see if the coolant is not leaking excessively. This may lower its levels, which can damage the engine. If the oil is leaking, it can reach the hot gas exhaust and produce foul-smelling smoke. Or worse, it can cause a fire.

Power Loss

Compressibility is one of the most desired characteristics of a head gasket sealer. If the auto part is not working at optimal conditions in this regard, one possible reason could be that air or fuel is escaping. The cylinder’s performance is reduced, which then causes the engine power to slow down.

Oil Contamination

Inside the engine block, the fuel and coolant should not leak into each other. But if the head gasket is not functioning correctly, this situation can occur. Its initial proof is the slush that forms on the inner part of the oil filler cap. This is not to say that any soft and viscous mixture you find underneath the lid is caused by this problem. So it’s worth checking the real root cause.

You may need to stop driving and have your engine repaired at this point. A professional mechanic will know what to do.

White Smoke

This is probably one of the most immediate and visual symptoms you can come across. If a head gasket fails, it can produce a white smoke that you can trace to the exhaust. It is probably an antifreeze leak that has reached the gasket and the cylinder. Here, the fluid turns into steam because of combustion. The white smoke can smell good.

Blue smoke, even if less rare, can also come out. And this is caused by an oil leak into the cylinder.

What is the Best Brand of Head Gasket?

Our top pick is the Fel-Pro Head Gasket Set. Since 1918, Fel-Pro has been serving auto parts worldwide, not just in the United States. Its full gasket packages are among its most sought-after products to date. The brand has a wide range of gasket sets to ensure compatibility with a variety of vehicles.

In this guide, we will zoom in on the HS26170Pt1. That may sound like some random numbers, but not for the car owners, technicians, and enthusiasts who have given it glowing reviews. Specifically, this kit caters to Subaru engines, including Baja Base, Forester, Impreza, Legacy, and Outback.

A few of the matches are:

  • Outback I with engine H4 – 2.5L 2458cc GAS MFI type EJ253 – 4 valve SOHC
  • Legacy L with engine H4 – 2.5L 2458cc GAS MFI type EJ253 – 4 valve SOHC
  • Impreza Outback with engine H4 – 2.5L 2458cc GAS MFI type EJ251 – 4 valve SOHC

You may visit the Fel-Pro website to find your match.

You will find a head gasket sealer made with MLS (Multi-Layered Steel), which manufacturers prefer for its high compressibility. This means it can fill distortions on sealing surfaces more effectively. The layers are also held together by rivets and dowel pins to ensure durability and alignment, respectively. Completing this flawless work is the blue gasket sealant coating.

The package also contains other parts, such as gasket clamps, valve seals, spark plug tube seals, and grommets, among others. All of these components pass through quality assurance. They make for an all-in-one solution, with each piece contributing to a leak-free engine. For instance, the gasket clamps use molded rubber for even application.

So whether you’re set for head reconditioning or valve grinding, this Fel-Pro offering has more than you need to get started. For around $150, it delivers value for your money. It’s a cheaper alternative to high-end gasket sets on the market. If it contains front or rear crank seals as well, it will have been a total bargain.

How Hard is it to Replace a Head Gasket Yourself?

If sealing the cracks and leaks aren’t solving the problem, changing the head gasket probably will. If you reach this point, make sure you have some experience in repairing engines.

Buying a gasket is the easy part. Replacement options for this auto part tend to be affordable. But installing the new head gasket may not be as easy as you think. Consider well if you’re up for the task. Otherwise, you may want to think about whether or not your car is worth a visit to the mechanic.

We’ll write about the steps on how to replace your head gasket in another article. So stay tuned!


With the best head gasket sealer, you can fix cracks and gaps in the auto part on your own. Following the directions on the packaging is crucial if you are DIY-ing the process. And with the top products on the market within reach, you can also rely on an effective solution to your gasket problem.

The BlueDevil Head Gasket Sealer is our #1 choice because of its compatibility with different materials. In an earlier section, you’ve learned that there are various materials used to make gaskets. This top-notch product works well on alloy, aluminum, cast iron, plastic, steel, and many more. Also, it is professional-grade yet affordable.

If you’re searching for value, you can also check out the Steel Seal Blown Head Gasket Fix Repair Sealer. The budget option would be The Right Stuff Gasket Maker by Permatex. The category runners-up also have their respective pros and cons you may want to consider. It may also depend on whether your engine runs on gasoline or diesel.

All things considered, you’re probably ready to shop and handle your head gasket issue. Finding the ideal sealant for your needs should not be nerve-wracking. And so is choosing the more cost-effective route to fix a problem.

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Relevant Resources:

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  2. Best Diesel Injector Cleaner in 2021 (Review & Buying Guide)
  3. 6 Best Motor Oils for BMW in 2021: Top Pick Reviewed

John Robinson
John Robinson

Howdy! I’m John Robinson from Levittown, New York. I am a mechanical engineer for 15 years and already had an established car repair company. I developed a personal relationship with cars since I was a kid. I always love the sounds and smell emitted by a car or truck and even at construction machinery. Since then I have been married but my love for cars only grew.