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Best Head Gasket Sealer (With Symptoms & Buying Guide)

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Written by The Motor Guy

Best Head Gasket Sealer 2019

Using the best head gasket sealer you can find can save you a load of money. One of the most expensive repairs your car could face is a blown head gasket. Repairs can cost well over a thousand dollars, sometimes even more than two thousand dollars depending on the vehicle and the damage involved.

A good alternative to replacing the head gasket can be a head gasket sealer. If you are reading this article because your car has been diagnosed with a bad head gasket, then choosing one of our best head gasket sealers below may be a possible solution.

Best Head Gasket Sealer Reviews


'Best Overall Head Gasket Seal'

Amazon.com prices as of  2019-05-25 at 12:22 UTC Details

Main Features
  • Super fast, permanent head gasket sealant
  • Contains carbon fibre sealing particles
  • Can also be used to seal intake gaskets,, heater cores and radiator leaks

Bar’s Leak HG-1 HEAD SEAL is a professional grade product, offering a permanent solution to most problems related to cylinder head leaks. It features a unique formula containing sealing particles bolstered with a special carbon fiber compound. This formula guarantees a long-term solution, and not just a temporary fix.

Product Highlights

Here is a quick summary of what to expect from this product:

  • Professional grade head gasket repair. This is not an emergency solution to drive your car for a few miles until you get home. The goal of this product is to seal the leak, permanently if possible.
  • Added benefits no other can offer. Only the formula of  Bar’s Leak HG-1 HEAD SEAL includes Xtreme Cool, a product that fights against engine overheating reducing coolant temperature.
  • Backed up by a solid and reputable company. Bar’s Leaks, the company behind HG-1 HEAD SEAL has been in business for almost 70 years. All its product line is completely developed and manufactured in the United States under the most strict quality controls.
  • Outstanding value for its price. Without any doubt, Bar’s Leak HG-1 HEAD SEAL has the best value of the market. For an insignificant price, you can perform a complete engine treatment saving you literally thousands of dollars in reparations.

Frequently Asked Questions (FAQ)

Do I need to flush the cooling system before using the product?

Absolutely not. You can safely use Bar’s Leak HG-1 HEAD SEAL without flushing your engine coolant. However, it’s advisable to check if your system is clogged or deficient before using this product.

Does this product works on diesel engines?

Yes. Bar’s Leak HG-1 HEAD SEAL works on both petrol and diesel engines.

Is this product safe for my engine?

Yes, it is. Bar’s Leak HG-1 HEAD SEAL is completely tested and guaranteed to do not clog your cooling system. It is also tested to be safe for a wide range of materials like cast iron, aluminum, and plastic.

Is it compatible with antifreeze?

Yes. Bar’s Leak HG-1 HEAD SEAL exclusive formula is 100% compatible and safe to use with all types of 50/50 water/antifreeze products (yellow, orange, pink, red, blue and green).

It is necessary to drain the radiator before or after using this product?

No, it’s not necessary. Bar’s Leak HG-1 HEAD SEAL should be kept circulating in the cooling system for added protection.

Do I need to remove the engine thermostat to use the product?

Not at all. You can use this product without removing anything from your engine. 

How long does it take the procedure?

Approximately 45 minutes (starting the procedure with your engine totally cold). Bar’s Leak HG-1 HEAD SEAL is one of the fastest solutions available.

Pros
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    Can be used in any engine
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    Can be used on a few different types of engine leaks
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    Works quickly and is very easy to use
Cons
  • Can only be used on engines that can idle for at least 15 mins without overheating

'Best Professional Grade Gasket Sealer'

Amazon.com prices as of  2019-05-25 at 13:22 UTC Details

Main Features
  • Heavy duty, professional grade sealant
  • One permanent solution for a range of engine leaks
  • Safe to use on all engine types

BlueDevil Head Gasket Sealer is a professional grade product that will repair any leak not only in the cylinder head but also on freeze plugs, heater cores and other components in contact with the coolant (with the exception of the radiator core). It offers a permanent solution to leaks, as far as you follow the exact product directions.

Product Highlights

Here is a quick summary of what to expect from this product:

  • Professional grade head gasket repair. This is not an emergency solution to drive your car for a few miles until you get home. The goal of this product is to seal the leak, permanently if possible.
  • Added benefits no other can offer. The BlueDevil Head Gasket Sealer complies with ASTM D1881 & ASTM D3147 standards.
  • Backed up by a solid and reputable company. BlueDevil, the company behind BlueDevil Head Gasket Sealer has been in business for many decades. All its product line is completely developed and manufactured in the United States under the most strict quality controls.
  • Outstanding value for its price. Without any doubt, BlueDevil Head Gasket Sealer has an excellent value for your money. For a fair price, you can perform a complete engine treatment saving you literally thousands of dollars in reparations.

Frequently Asked Questions (FAQ)

Do I need to flush the cooling system before using the product?

Yes, you will need to do so.  BlueDevil Head Gasket Sealer requires you to flush your old engine coolant and then use a coolant system cleaner to get rid of any remaining deposit. Then you need to use the product with WATER to perform as expected.

Does this product works on diesel engines?

Yes. BlueDevil Head Gasket Sealer works on both petrol and diesel engines.

Is this product safe for my engine?

Yes, it is. BlueDevil Head Gasket Sealer is completely tested and guaranteed to do not clog your cooling system. It is also tested to be safe for a wide range of materials like cast iron, aluminum, and plastic.

Is this product compatible with antifreeze?

No. As mentioned above, BlueDevil Head Gasket Sealer can only be used with water.

It is necessary to drain the radiator after using this product?

Yes, BlueDevil Head Gasket Sealer works with water, after completing the repair procedure you will need to drain the product and fill your system with the appropriate engine coolant, however, you won’t need to flush and clean the system again, just add the new coolant.

Do I need to remove the engine thermostat to use the product?

Yes, this is mandatory for using BlueDevil Head Gasket Sealer. Once you finish the repair procedure you will need to reinstall the thermostat again.

How long does it take the procedure?

Approximately one and a half hour to two hours (starting the procedure with your engine totally cold). BlueDevil Head Gasket Sealer is one of the fastest solutions available. 

Pros
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    Can be used on any engine type
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    Offers a simple, permanent solution to leaks
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    Multi-purpose professional grade sealant
Cons
  • You must remove the engine thermostat before using
  • You also need to replace the coolant after usage

'Best DIY Head Gasket Seal'

Amazon.com prices as of  2019-05-25 at 12:22 UTC Details

Main Features
  • Fast, DIY, permanent head gasket sealant
  • Can be used on a range of engine leaks
  • Backed by a 100% money-back guarantee

Steel Seal is a DIY product that will permanently repair any cylinder head leak. It fixes leaks using its exclusive formula that repair blown head gaskets, cracked heads or block. 

Product Highlights

Here is a quick summary of what to expect from this product:

  • Top quality head gasket fix. This is not an emergency solution to drive your car for a few miles until you get home. The goal of this product is to seal the leak, permanently if possible.
  • Added benefits no other can offer. One key benefit of Steel Seal is that it offers a lifetime guarantee. If the product fails to permanently seal the head gasket leak you will receive an additional product at no cost.
  • Backed up by a solid and reputable company. This is by no means a new product. Steel Seal has been in the market for more than 18 years, fixing leaks all around the world.

Frequently Asked Questions (FAQ)

Do I need to flush the cooling system before using the product?

It is advisable to do so.  Steel Seal is not 100% compatible with all antifreeze formulations so is preferable to flush your old engine coolant and then use a coolant system cleaner to get rid of any remaining deposit. Then you can to use the product with WATER to perform as expected.

Does this product works on diesel engines?

Yes. Steel Seal works on both petrol and diesel engines.

Is this product safe for my engine?

Yes, it is. Steel Seal is completely tested and guaranteed to do not clog your cooling system. It is also tested to be safe for a wide range of materials like cast iron, aluminum, and plastic.

Is this product compatible with antifreeze?

No. As mentioned above, Steel Seal is not 100% compatible with all types of antifreeze.

It is necessary to drain the radiator after using this product?

Yes, Steel Seal works better with water, so after completing the repair procedure you will need to drain the product and fill your system with the appropriate engine coolant, however, you won’t need to flush and clean the system again, just add the new coolant.

Do I need to remove the engine thermostat to use the product?

Not at all. You can use this product without removing anything from your engine. 

How long does it take the procedure?

Approximately one hour (starting the procedure with your engine totally cold). Not at all. You can use this product without removing anything from your engine. Steel Seal is one of the fastest solutions available.

Pros
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    Can be used on any engine type
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    Provides a simple, permanent solution
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    No need to remove thermostat before use
Cons
  • It's necessary to replace the coolant after usage as it works best with water

'Best Sealant for Common Engine Leaks'
ATP AT-205 Re-Seal Stops Leaks, 8 Ounce Bottle
2,373 Reviews

Amazon.com prices as of  2019-05-25 at 12:22 UTC Details

Main Features
  • Multi-purpose engine leak sealant
  • Easy to use, DIY solution
  • Professional, fast acting formulation

ATP AT-205 Re-Seal is a different kind of DIY product. It’s not formulated specifically to seal head gasket leaks but to stop common engine, transmission, power steering, differential, and any other hydraulic system leaks. Unlike other products, ATP AT-205 Re-Seal is used in the engine oil (not the engine coolant/antifreeze) to fight rubber seals leaks.

Product Highlights

Here is a quick summary of what to expect from this product:

  • Top quality head gasket fix. This product is formulated to stop rubber based gasket leaks for long periods of time.
  • Added benefits no other can offer. As mentioned before, ATP AT-205 Re-Seal can be used to stop almost all kind of vehicle leaks not only engine leaks. However, be warned that this product is not intended for head gasket repair, only rubber type gasket leaks, like the crankshaft seal for example.
  • Backed up by a solid and reputable company. This is by no means a new product. ATP AT-205 Re-Seal has been in the market for many years, fixing leaks all around the world.
  • Outstanding value for its price. Without any doubt, ATP AT-205 Re-Seal has an excellent value for your money. For a ridiculous price, you can perform a complete engine treatment.

Frequently Asked Questions (FAQ)

Do I need to flush the engine oil before using the product?

Absolutely not. ATP AT-205 Re-Seal can be used with your current oil no matter how many miles it has.

Does this product works on diesel engines?

Yes. ATP AT-205 Re-Seal works on both petrol and diesel engines.

Is this product safe for my engine?

Yes, it is. ATP AT-205 Re-Seal is completely tested and guaranteed to be safe for your engine, transmission, power steering, differential, and hydraulic components.

Is this product compatible all types of engine oil?

Yes, it is. ATP AT-205 Re-Seal is completely safe to use with mineral, blended and fully synthetic engine oil.

It is necessary to drain the oil after using the product?

Not at all. You can continue using your engine oil until the next service.

How long does it take the procedure?

Approximately 5 hours. You need to use the correct amount of product (depending on your engine size) and then drive normally.

Pros
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    Can be used on any engine type, petrol or diesel
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    Provides a fast permanent solution
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    Suited to rubber seal repair
Cons
  • Not actually a head gasket sealant, suited to rubber seal repair instead

'Best Multi-Purpose Head Gasket Sealant'

Amazon.com prices as of  2019-05-25 at 13:22 UTC Details

Main Features
  • Multi-Purpose Sealant that can be used on virtually any type of engine leak
  • Fast acting, permanent solution
  • Easy to use - No draining or flushing the coolant system

K-Seal is a professional grade multi-purpose product that aims to permanently seal cylinder head gasket, block, radiator, and heater leaks. 

Product Highlights

Here is a quick summary of what to expect from this product:

  • Professional grade head gasket repair. This is not an emergency solution to drive your car for a few miles until you get home. The goal of this product is to seal the leak, permanently if possible.
  • Added benefits no other can offer. Unlike similar products, K-Seal is a real multi-purpose leak sealant that can be used on any engine type.
  • Backed up by a solid and reputable company. This is the only product on this list tested in UK and US and passing the ASTM D3147 test.
  • Best value for its price. You won’t find any other product offering so many benefits at this price. K-Seal has the best cost-benefit ratio. For a low price, you can perform a complete engine treatment saving you literally thousands of dollars in reparations.

Frequently Asked Questions (FAQ)

Do I need to flush the cooling system before using the product?

Absolutely not. You can safely use K-Seal without flushing your engine coolant. However, it’s advisable to check if your system is clogged or deficient before using this product.

Does this product works on diesel engines?

Yes. K-Seal works on both petrol and diesel engines.

Is this product safe for my engine?

Yes, it is. K-Seal is completely tested and guaranteed to do not clog your cooling system. It is also tested to be safe for a wide range of materials like cast iron, aluminum, and plastic.

Is this product compatible with antifreeze?

Yes. K-Seal exclusive formula is 100% compatible and safe to use with all types of 50/50 water/antifreeze products (yellow, orange, pink, red, blue and green).

It is necessary to drain the radiator before or after using this product?

No, it’s not necessary. K-Seal should be kept circulating in the cooling system for added protection.

Do I need to remove the engine thermostat to use the product?

Not at all. You can use this product without removing anything from your engine. K-Seal does not involve any additional work on your car.

How long does it take the procedure?

Approximately 45 minutes (starting the procedure with your engine totally cold). K-Seal is one of the fastest solutions available.

Pros
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    Can be used on any engine type
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    Suitable for fixing leaks in head gasket and any part of the coolant system
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    No need to drain or flush the system
Cons
  • None

'Best Nanotechnology Head Gasket Sealant'

Amazon.com prices as of  2019-05-25 at 12:22 UTC Details

Main Features
  • Uses nanotechnology to create a strong permanent seal
  • Can fix head gaskets, coolant system leaks & engine block leaks
  • Suitable for all use in all engine types

K&W Nanotechnology Permanent Head Gasket & Block Repair is a professional grade product that will seal any leak in contact with the antifreeze coolant thanks to its exclusive nanotechnology formula.

Product Highlights

Here is a quick summary of what to expect from this product:

  • Professional grade head gasket repair. This is not an emergency solution to drive your car for a few miles until you get home. The goal of this product is to seal the leak, permanently if possible.
  • Added benefits no other can offer. The K&W Nanotechnology has a unique formula that use nanotechnology to fill cracks and seal leaks. This nanotechnology creates a strong molecular bond that permanently seals any kind of leak.
  • Backed up by a solid and reputable company. K&W, the company behind K&W Nanotechnology has been in business for many years. All its product line is completely developed and manufactured in the United States under the most strict quality controls.
  • Outstanding value for its price. Without any doubt, K&W Nanotechnology has an excellent value for your money. For a fair price, you can perform a complete engine treatment saving you literally thousands of dollars in reparations.

Frequently Asked Questions (FAQ)

Do I need to flush the cooling system before using the product?

Yes, you will need to flush the system.  K&W Nanotechnology requires you to flush your old engine coolant and then use a coolant system cleaner to get rid of any remaining deposit. Then you need to use the product with water to perform as expected.

Does this product works on diesel engines?

Yes. K&W Nanotechnology works on both petrol and diesel engines.

Is this product safe for my engine?

Yes, it is. K&W Nanotechnology is completely tested and guaranteed to do not clog your cooling system. It is also tested to be safe for a wide range of materials like cast iron, aluminum, and plastic.

Is this product compatible with antifreeze?

No. As mentioned above, K&W Nanotechnology can only be used with water.

It is necessary to drain the radiator after using this product?

Yes, K&W Nanotechnology works with water, after completing the repair procedure you will need to drain the product and fill your system with the appropriate engine coolant.

Do I need to remove the engine thermostat to use the product?

Yes, this is mandatory for using K&W Nanotechnology. Once you finish the repair procedure you will need to reinstall the thermostat again.

How long does it take the procedure?

Approximately 14 hours. This product requires a minimum of 12 hours with the engine off to complete the nanotechnology bond process.

Pros
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    Can be used on an engine type
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    Fixes a wide range of leaks by creating a permanent seal
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    Uses nanotechnology to create a stronger seal
Cons
  • Not fast acting, takes 14 hours to complete
  • You must flush the coolant system before use

Best Head Gasket Sealant Buying Guide



What's a head gasket?

Simply put, the head gasket seals the cylinder head/engine block assembly. It is quite a unique gasket not like any other in your vehicle. It has special o-ring type passages but also high-temperature materials and alloys that ensures that engine compression won’t leak. Due to its important role and complex nature, this is one of the most expensive gaskets of the engine, designed to last hundreds of thousands of miles.


4 Symptoms of a blown head gasket

head gasket sealer

Fortunately, it’s very easy to detect a blown head gasket. Below are listed the most common symptoms:

1. White smoke coming from the exhaust tail

If you are experiencing this symptom, then look no further. You definitely have a blown head gasket. The white smoke is produced by the coolant that reaches the cylinder when the engine is off. During the combustion process, the coolant evaporates and manifest as a water vapor smoke.

2. Antifreeze mixed with engine oil

This is a collateral consequence of the leak explained above. When the engine coolant reaches the cylinder it drips to the oil pan and mixes (due to the positive pressure) with the engine oil. The result is a whitish oil, with a characteristic smell.

3. Bubbles in the overflow tank

The positive pressure created during the compression and combustion phases literally burns the head gasket and usually finds its way into the cooling system. When that happens, the entire engine cooling system is pressurized by the compressed air coming from the combustion chamber. This causes perceptible bubbles in the radiator and the overflow tank.

4. Engine overheating

As a direct consequence of the head gasket leak, the engine cooling system performance will drop significantly. Air bubbles behave totally different from a thermodynamic point of view, affecting the radiator ability to dissipate heat.


How to avoid A blown head gasket

In most cases, the head gasket failure is caused by engine overheating. The cylinder head gasket is designed to work at engine normal operating temperature. If your vehicle is running hotter than normal and you keep using it during extended periods of time then you are risking your head gasket.

The best way to avoid a blown head gasket and thus skip the expensive implications of a head gasket repair is knowing your car. Keep an eye on your instrument panel. As soon as you perceive that your car is running hotter than usual perform a coolant system check. There are special tools, very easy to use, that can help you diagnose a clogged radiator or a coolant leak. Prevention is your best strategy against a blown head gasket.


Alternatives To Using A Head Gasket Sealant

Once you have a blown head gasket your options become very limited. You can use a sealant and perform a head gasket fix or you can replace the gasket.

new head gasket

A replacement head gasket can sometimes be the only option

Driving your car with a blown head gasket is not an option. The immediate consequences could be catastrophic. Engine overheat could literally warp your cylinder head and leave the engine block beyond repair.

Since replacing the head gasket is so expensive, if possible, the best alternative remains using a good quality head gasket seal.