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10 Best Head Gasket Sealers: Product Reviews And Buying Guide

Best Head Gasket Sealers

Owning a car has its perks. However, years of driving and a lack of maintenance can lead to a handful of problems.

It can be anything — from simple hiccups on the road, the feeling that it doesn’t run like it used to anymore or even a white smoke that’s coming out of your tailpipe. All these and more indicate your car is in distress. One of the most common though is a blown head gasket.

Sure enough, the auto-repair shop breaks the bad news and it’s going to charge you around $2,000 to get it fixed. It doesn’t make sense to you and you’re this close to breaking down and regretting every buying a car in the first place.

Before you go into a paranoiac overdrive and wish you just use Uber instead, let me tell you that there are a handful of other solutions you can try before burning a deep hole in your pocket.

In this guide, I will let you in on what a head gasket is. Signs and symptoms of a blown head gasket are and what the best head gasket sealers are to fix your problem. I’ll also let you in on tiny nuggets of car knowledge along the way.

Even if you have very little to no knowledge about this one, I’ll make sure you’ll be confident enough to repair it yourself. Besides, there’s nothing more badass than being your own car guy or car girl, right?

The Best Head Gasket Sealer

There are a lot of head gasket sealers available in the market. One that could serve you poorly may work better for another car model. Factors like compatibility and the number of cylinders you’re working with are what you should account for. So remember to choose the right one that best suits your car.

It won’t hurt asking a professional on this one. After all, that’s better than wasting your money and creating more problems.

Here are my personal recommendations on the best head gasket sealers you can use:

1. ATP AT-205 Re-Seal Stops Leaks

ATP AT-205 Re-Seal Stops Leaks

Compatibility plays a huge factor in choosing the right sealant, and as such, my first pick would be the ATP AT-205 Re-Seal Stops Leaks, 8 Ounce Bottle. What is it that makes this product a very competitive sealant?

If you are using petroleum distillate rubber conditioners, apparently, it can oftentimes weaken rubber seals. This stuff however, is non-toxic. That’s a massive plus to us! After all, who wants something that can break seals like a mush over time?

This is another amazing product with an exclusive formulation that is highly recommended to eliminate oil leaks. Other than that, it isn’t harsh to the internal bearings and components. With just a full 8oz bottle it can treat a 6qt capacity with maximum success.


  • Amazon best seller
  • Comes in 8 oz
  • Fast acting professional sealer
  • Compatible with various oil types
  • Safe and easy to use
  • Great value for money


  • Not for transmission and power steering

2. Bar’s Leak HG-1 Head Seal Blown Head Gasket Repair

Bar’s Leak HG-1 Head Seal Blown Head Gasket Repair

This may not be the number one but it surely deserves the second spot as the alternative solution to the ATP AT-205. I’m talking about the Bar’s Leak HG-1, a professional all in one permanent fix for all your head gasket problems with just one single dose.

Whether the vehicle is using gas, diesel, turbocharged, and racing engines, with 4,5,6,8, or even 10 cylinders, it works very well. This is precisely what makes the Bar’s Leaks Cooling Sealant a great choice.

This brand comes with a professional grade. Moreover, this particular sealant is highly recognized for its compatibility with various engines. It highlights its “Xtreme Cool” patented ingredient that helps decrease the water temperature and stops the overheating of the engine.


  • Amazon best seller
  • Comes in 33.8 oz
  • Safe and easy to use
  • Antifreeze compatible
  • No flushing required
  • Limited lifetime warranty


  • Not suitable for interior leaks

3. K-Seal Coolant Leak Repair ST5516

K-Seal Coolant Leak Repair ST5516

Taking the third spot is the K-Seal ST5516 HD Multi-Purpose One Step Permanent Coolant Leak Repair. What is it that makes this sealant brand quite special? It is reported to fix a leak problem in 3 minutes. Yep, you read that right. It’s as quick, easy and effective.

Believe it or not, it has proven itself to fix a problem within the said time frame. One of its advantages is it can mix with any kind of antifreeze, which not all sealers are capable of. It also eliminates the hassle of draining or flushing.

What better product that is as simple as “pour and go”? It potentially saves you time and saves you and your wallet the pain in case you get stuck in the midst of a panic trip. These are the plus factors that gave this sealant a high recognition.


  • Comes in 16 oz
  • Multipurpose formula
  • Safe and easy to use
  • Works with all types of antifreeze
  • Good value for money


  • May clog heater core if not used properly

4. BlueDevil Head Gasket Sealer

BlueDevil Head Gasket Sealer

Ranking number 4 on the list is the BlueDevil HEad Gasket Sealer, which claims to be the perfect alternative solution for those costly and time-consuming repairs by offering you a permanent fix guarantee.

This is without a doubt the most trusted brand of sealant in the market today, especially for cars with 4 or 6 cylinder vehicles. What gives this name “The Boss” reputation? It boasts of a design that favors the non-auto savvy well. Furthermore, it’s made for a very easy do-it-yourself solution.

The BlueDevil Pour and Go is popular because it eases the difficulty level of applying and sealing the gaps. It may not be a permanent fix but it has a formula of high-temperature adhesive that includes sodium silicate has a remarkably high success rate among many users.


  • Comes in 32 oz
  • Available in 1 and 6 pack
  • High-temperature adhesive
  • Safe and easy to use
  • Good value for money


  • Poor customer service

5. Steel Seal Blown Head Gasket Fix – 6 Cylinder

Steel Seal Blown Head Gasket Fix – 6 Cylinder

Another sealant choice is the Steel Seal Blown Head Gasket Fix Repair Sealer. If you are already in a conundrum trying to find a simple do-it-yourself pour -in head gasket fix for your 6 cylinder motor, this stuff really works.

Regardless if your vehicle is gasoline or diesel, this product has the proven ability to deliver a strong “seal like a steel” effect. It holds up perfectly under normal driving conditions, even when using your car’s air conditioning system.

Plus, what I like about this product more is that the company offers a money-back guarantee, just in case you are highly suspicious of a fix in a bottle. That itself is an additional reason as to why this product is worth it.


  • Award winning head gasket sealer
  • Fast acting permanent fix
  • Works for 6 cylinder engines
  • Safe and easy to use
  • 100% money back guarantee


  • Not compatible with antifreeze

6. K&W 401232 Permanent Head Gasket & Block Repair

K&W 401232 Permanent Head Gasket & Block Repair

Next up is the K&W 401232 Permanent Head Gasket & Block Repair, an excellent head gasket sealer that’s engineered with nanotechnology to cure all your head gasket problems and more in half the time it takes and twice the strength of many other sealers out there.

This baby can permanently solve issues with your engine block, heater core, freezer plugs, cooling systems, cylinder heads, and radiators. That’s why it’s so perfect for repair and maintenance works on trucks and other automobiles.

The only thing is, you will need to flush all antifreeze in your cooling system before adding the product to the radiator so it doesn’t cause any problems. But other than that, it’s safe and easy to use, and an excellent product all in all.


  • Amazon’s Choice product
  • Comes in 32 oz
  • With nanotechnology
  • Fast acting permanent sealer
  • Double your money back guarantee


  • Not compatible with antifreeze

7. K&W 401224-6 FiberLock Head Gasket & Block Repair

K&W 401224-6 FiberLock Head Gasket & Block Repair

Another option you’ve got from K&W is the K&W 401224-6 FiberLock Head Gasket & Block Repair. It’s a nanotechnology reinforced head gasket sealer that is engineered with military strength fibers to give you superior quality permanent repairs.

It can effectively solve all your problems with your head gaskets, engine blocks, cylinder heads, and cooling systems. And, laboratory tests show that it can even seal larger holes with significantly less fluid loss.

What’s more, is that it also works with antifreeze and plain water, so no flushing is required prior to use. It also comes with a Cool X conditioner to lower your engine’s operating temperature as this sealer passes through your cooling system.


  • Amazon’s Choice product
  • Comes in 32 oz
  • With Cool X conditioner
  • Safe and easy to use
  • Double your money back guarantee


  • May clog cooling system if not used properly

8. CRC K&W 401016 Metallic Block & Radiator Seal

CRC K&W 401016 Metallic Block & Radiator Seal

Yet another one from K&W that you should definitely consider trying out is the CRC K&W 401016 Metallic Block & Radiator Seal. it’s a professionally formulated sealer that effectively seals leaks in your cooling systems and more.

In fact, it works as a permanent and cost effective solution in fixing all your problems with leaks, cracks, and blown head gaskets, making it perfect for engine blocks and radiators. It won’t wash away, it can withstand extreme temperatures, and it will extend your vehicle’s service life.

This sealer has a molecular composition that makes it strong as steel when applied as a sealer on aluminum and cast iron engine blocks, and on aluminum, copper, and bi-material radiators and heater cores. It’s also specially designed for water-cooled diesel and gasoline vehicles.


  • Amazon’s Choice product
  • Comes in 16 oz
  • Suitable for water-cooled engines
  • Permanent molecular bond
  • Money back guarantee


  • Not compatible with antifreeze and oil

9. Permatex 80697 Copper Spray-A-Gasket Adhesive Sealant

Permatex 80697 Copper Spray-A-Gasket Adhesive Sealant

You might also want to try the Permatex 80697 Copper Spray-A-Gasket Adhesive Sealant. It’s a high temperature aerosol spray sealant that not only fills and fixes various surface imperfections and hot spots, but gives you various added benefits as well.

These include an improved heat transfer and dissipation, as well as prevention of premature gasket burnout. It works excellently on cylinder head gaskets, exhaust manifold gaskets, and many other high temperature applications.

It also completely resists all types of automotive fluids to fully protect you from leaks and whatnot.


  • Comes in 9 and 12 oz
  • Available in 1 and 6 pack
  • Aerosol type sealant spray
  • Works for nonabsorbent surfaces
  • Great value for money


  • Container may sometimes be defective

10. Irontite All Weather Seal

Irontite All Weather Seal

Finally, I also recommend the Irontite All Weather Seal, which is a superior professional choice for an all purpose and all weather sealant that works fast and lasts long in effectively sealing coolant leaks and more.

It works effectively in solving issues in your radiator, head gasket, and engine block, especially since it’s engineered with a chemical bonding formulation that stays in your suspension and won’t settle out.

Plus, it can also mix with your antifreeze to ensure that all existing and future leaks are resolved without having to flush anything, so it’s easy and convenient to use. It’s also compatible with both gasoline and diesel engines.


  • Comes in 16 oz
  • Chemical bonding formula
  • Safe and easy to use
  • Works for gas and diesel engines
  • Works with antifreeze


  • Not as long lasting as others

Head gasket sealer buying guide

One of the best, easiest, and cheapest ways to protect your engine, resolve minor problems, and prevent more serious issues from arising anytime soon is by using a high quality head gasket sealer.

That being said, you can’t just buy the first sealant you come across. There are many important factors that you need to consider if you want to make sure you are buying the best head gasket sealer that works for you and your car.

In order to help you out, I’ve come up with this buying guide that explains everything you need to know about head gasket sealers:


The first and most important thing you need to watch out for is whether the sealer is compatible with your engine in the first place. Otherwise, rather than fixing the problem, you might just make it infinitely worse.

There are head gasket sealers designed for gas vehicles, others for diesel engines, and some work only with water based cooling systems, although you’ll also find sealers that can work well with antifreeze.


Aside from sealing your head gasket and protecting you from leaks and other engine issues, head gasket sealers are often advertised as multipurpose products, meaning, they also double as temporary or permanent fixes for other engine-related problems.

These include issues with the radiator, engine block, cooling systems, cylinder heads, and so on. As such, you’ll be saving money by buying a multifunctional sealer if you need to deal with these other problems rather than spending on a solution for each issue individually.

Ease of use

These gasket sealants come in many different formulations. Some are poured in liquids, while some are aerosol sprays. Some require you to flush antifreeze and other compounds in your engine and cooling system beforehand, while some are just pour and go.

If you want a quick, easy, and simple solution, try to look for a pour and go bottle that does all the work for you, just make sure that it actually works effectively even without you having to do any preliminary steps.

Action time

You’d also want something that works fast so you don’t have to wait for a long time before you can start your engine again and get back on the road. To give you an idea, a majority of sealants take about an hour or so to do its job completely.

That said, it’s still more important to make sure that the sealant works well even though it may take a bit more time, rather than one that works quickly but only lasts for a short period of time.


In relation to what I just mentioned, how permanent the effects of the sealant is also highly important. What you want here is something that actually works as a permanent fix, rather one you’ll keep having to apply.

Besides, it’s not like you can easily monitor when it’s time to pour in some sealant again, since you’ll only notice this when problems start arising again, and you really wouldn’t want to wait for that to happen.

Head gasket sealer FAQs

Head gasket sealer FAQsMany of today’s vehicles are manufactured with an engine block and a cylinder with a head bolted to the top. In this area, you will find the cylinders, valves, rocker arms and pistons. Between the engine block and the cylinder head lies the head gasket. It’s reminiscent of the plastic seal often seen in six-pack sodas or beers, just in case you’re wondering what it looks like.

The head gasket exists to separate both the cylinder head and engine block so if one or two breaks down, they can be repaired individually. It needs to seal the coolant passages, oil passages and the area where the fuel, air, spark, and compression take place.

How to determine if you have a blown head gasket?

Believe it or not, detecting a blown head gasket is fairly easy. Once you spot the signs and symptoms, you’ll be on your way to preventing it from becoming a full-scale problem or do an efficient quick fix to make it right.

External oil leaks

One of the most common signs of a blasted head gasket is an external oil leak. However, we often mistake these oil leaks as coming from the valve or somewhere below the transmission thanks to gravity. It’s best to check if there are problems between the oil passage and outside.

If your patience is wearing thin from constantly adding coolant to your head gasket, you should be on the look-out for seepage below the exhaust manifold.

Keep in mind: Visual inspection is not a 100% accurate method to determine a leak. Despite not seeing any visible leaks or the cooling system pressure test seems to rule out a water pump, it doesn’t mean the leaks don’t exist. Try checking that for bubbles in your radiator.

Contaminated oil

If you see a milk-like ring around the cap, chances are your coolant has been mixed with your oil. It’s now contaminated and can lead to graver consequences. You may see this also on your engine oil dipstick or especially if you’re noticing white smoke coming out from your exhaust.

I hate to tell you this but this one is totally a deal-breaker. What you need to do now is to have your head gasket replaced and your oil changed. It’s also good to give your engine a good cleaning beforehand because some of these symptoms are quite visible.

Tinted spark plugs

A tinted spark plug is another sign. One manifestation of which is your coolant spraying out of the holes in your spark plug. Another indication is when you use a green coolant and there is a green hue on your spark plug.

Again, the best thing you can do here is to replace the gasket.

Excessive pressure

One more way to determine if you’re working with a blown head gasket is an excessive pressure that causes the radiator cap to blow off. It can also end up cracking your radiator tank or blow a radiator hose.

Whichever is the weakest part of the cooling system is, it will fail and will eventually lead to bigger problems.

Severe overheating

This, my friend, is perhaps the most nerve-racking problem. It brings the temperature too hot until it ruptures the metal ring around the piston, which can end up giving you a major migraine — and a massive bill to pay.

All these and more can indicate a blown-out head gasket. That being said, you’re not totally helpless when it comes to fixing a bad gasket. In fact, fixing the leak is one that you can definitely work with.

Poor engine

If your engine has been noticeably running poorly, then it might be another sign of a blown gasket. You could experience a slow or unresponsive engine, a loss of compression or overheating.

What happens when the head gasket is blown?

What happens when the head gasket is blown?When all the indicators of a bad head gasket are present, such as poorly running engine and irregular overheating, you need to conduct an external leak test to check if your car or truck’s head gasket is giving in before it causes more damage to its nearby parts.

Bear in mind that anything that speaks “engine” is quite touchy. However, nothing else can throw someone more shade than the severity and figured expense of replacing this part through a trusted mechanic. You need to brace yourself as it can make your brain twitch and your wallet cry.

It varies greatly on the year, makes, and model of the vehicle. The cost also depends on the size of the engine, not to mention it has more than one failure type on top of other possible multiple failures. Some symptoms are even more misleading. In other words, it can cost thousands of dollars.

Does it sound like a conundrum? Sure it does. The first thing that pops in our minds is, of course, the first-hand resolution depending on how bad the seepage is.

The question is: Are there any easier ways and cheaper options? Yes, of course!

This is when the best head gasket sealers and sealants can save you from the distress of spending a huge chunk of money.

The solution: a head gasket sealer

Also known as a gasket sealant, a head gasket sealer is a spray, paste or glue that will not only keep your gasket in place. It also serves to combat fluid leakages and reduce the likelihood of your car parts from rubbing each other.

Do remember that these sealants may wear out over time. No matter how tight they started out, they may loosen up and weaken soon enough. That’s why it’s best to know which sealants are the best, and how to apply them correctly.

How to use a head gasket sealer

Even these automotive repair products have different “special” elements that are not the same as the others. Some are specialized with properties suitable for aluminum, cast-iron engine blocks & cylinder heads.

Moreover, there are brands that are not compatible with antifreeze, and, or not requiring to remove the thermostat or drain the cooling system. This is exactly why you need to find the right sealer and learn how to put it to use.

Don’t fret. I’m here to help you every step of the way. Once you’ve chosen which sealant you want to use, here’s how to apply it effectively.

  1. Before you gush all the liquid in, always shake the bottle to ensure you have the product mixed thoroughly.
  2. Flushing is recommended but may not even be necessary unless the system is dirty. However, I still recommend it. Drain and flush your radiator using either a flushing agent or 2 gallons of distilled water until the fluid that drains out of the radiator is clear.
  3. Before you give it a whirl, fill the radiator with water but leave enough room for the recommended amount of sealer. Some vehicles, depending on its number of cylinders, may need a larger amount of sealer, particularly the 8 and 10 cylinder vehicles.
  4. Start the car, turn the heat on maximum and let it idle for 15 to 30 minutes or whatever is stated on the product’s instructions. Make sure that the fan is on high (it is very important!)
  5. After 30 minutes or so, let the engine cool and flush out the head gasket sealer. Check the temperature. If the heat backs off and hits the right range you can hit the road again in no time but keep observing it for a couple of days for any leaks.


Applying the right sealant is relative. It really all depends on how bad the leak is and the type of vehicle you have. These products are all worth a shot if you want to skip the dirty work.

There are a few skeptic vehicle owners who do not want to rely on head gasket sealants and sealers because they’re afraid that such chemical solutions might create more problems in the future. This concern has reached the attention of many automotive product manufacturers, which is why they came up with non-toxic formulas.

Blown head gaskets shouldn’t be a foreign territory if you drive a car. Consider this guide to help prevent and fix it in the future. Who knows? You might just find yourself helping a buddy out too soon enough.

I highly recommend the ATP AT-205 Re-Seal Stops Leaks. It’s a professional grade fast acting permanent sealant that’s compatible with almost all types of engines and engine oils, has a non-toxic formulation, and gives you great value for your money.

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