Best Head-Gasket Sealers: Permanently Solve Coolant and Engine Oil Leak Problems

Permanently seal cracks and coolant leaks with our top picks for head-gasket sealer.

byNoelle Talmon|
Engine & Motors photo

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BYNoelle Talmon/ LAST UPDATED ON May 12, 2023

Faulty head gaskets are no fun to deal with. This type of malfunction can cause a lot of issues, including engine misfires and oil leaks. While a bad head gaskets will eventually need to be replaced in most cases, gasket sealers just might buy you some time to get you by until you can afford to do so. There are numerous head gasket sealers available online and in stores, some intended to be used as mentioned, others to promote a seal during installation. This guide will help you decide which is best for your situation.

Best Overall
Steel Seal Blown Head Gasket Fix Repair Sealer  

Steel Seal Blown Head Gasket Fix Repair Sealer  

An easy-to-use product that works well with both diesel and petrol engines. It’s a multi-use sealant that solves problems associated with head gasket leaks, heater core, and freeze plugs.
  • Easy to work with
  • Helps eliminate overheating problems
  • Improves vehicle mileage
  • Reduces smoke emissions and oil consumption
  • Works well for old trucks that cannot hold water
  • Backed by a 100 percent money-back guarantee
  • Expensive
  • Will only work well if you flush the engine first
Best Value

K-Seal ST3501 HD

An affordable sealant known to solve common problems fast and blends easily with antifreeze. Can eradicate tapping or flushing and repair other problems such as freeze plugs, heater cores, warped gaskets, and cracked heads.
  • Permanent solution to coolant leak repairs
  • Mixes well with all antifreeze
  • Doesn’t require engine flushing or draining
  • Fixes multiple problems
  • Affordable
  • Sealant might not work well if the head gasket has extensive damage
  • Discolors some brands of antifreeze
Honorable Mention

BlueDevil Head Gasket Sealer

A head gasket sealer that is compliant with ASTM standards and permanently seals the blown head gasket on all types of engines. The sealer is safe and easy to use.
  • Sealant is a permanent solution that works well during any weather condition
  • Prevents coolant leaks
  • Prevents the loss of radiator fluids
  • Helps with resolving cold start rough idle
  • Manufactured by a reputable company
  • You may have problems with the thermostat after using the product
  • May block the cylinder tubes and passages

Summary List

Our Methodology

We selected this sturdy, extensive selection of head gasket sealers based on user experiences, effectiveness, price, and value. Some are on the higher-dollar side, some are very inexpensive. There are many sealers out there that have questionable effectiveness, but these products' reviews indicate that all hope is not lost. While a liquid sealer isn't the most optimal fix for a head gasket, it could be enough to stave off a lofty repair bill for a good, long while. But of course, your mileage may vary. For more on how we select products for our reviews, check this out.

Best Head Gasket Sealers Reviews & Recommendations

The Steel Seal gasket sealer comes in two bottles that are enough for people with bigger engines such as eight-cylinder engines. The product comes with easy-to-follow instructions, though you need slight automotive knowledge to use it. This sealer is designed for solving different blown head gasket symptoms, which include white smoke, engine overheating, external leaks, and watery oil.


  • Country of Origin: USA
  • Size: 16 oz
  • Manufacturer Part Number: ‎6CYL001
  • Pros

  • Seals fast
  • Designed to work in older engines
  • Works in gasoline and diesel engines
  • Cons

  • Only works when a flush is performed prior to use
  • Expensive
  • The K-Seal Coolant Leak Repair is a “shake, pour, and go” head gasket sealer that comes with an affordable price tag. This product’s standout feature is the fact that it’s compatible with any antifreeze product, which eliminates the need to flush out the coolant system before application. It’s a multipurpose product and you can safely use the sealant to solve other leakage issues related to the heater core, engine block, water pump casing, and freeze plugs.


  • Country of Origin: USA
  • Size: 16 oz
  • Manufacturer Part Number: ST5516
  • Pros

  • Inexpensive
  • Does not require an engine flush prior to use
  • Treats other coolant leaks
  • Cons

  • Reported coolant discoloration post-use
  • Users report effectiveness in small leaks only
  • The BlueDevil gasket sealer is an easy-to-use sealer that saves you money in repair bills for your car. It’s a professional-grade head gasket sealer that also solves leakage issues associated with the heater cores, freeze plugs, and other components associated with the coolant apart from the radiator core. As long as you follow the instructions provided, the sealer provides a permanent leakage repair solution. 


  • Country of Origin: USA
  • Size: 32 oz
  • Manufacturer Part Number: 38386
  • Pros

  • Works on cracked, leaking, and warped heads
  • Works with any cylinder count
  • Can simply dump into the engine
  • Inexpensive price
  • Cons

  • May cause blockages in the engine
  • Works most effectively with fresh coolant
  • This gasket sealer and belt dressing comes in both an eight-ounce and four-ounce can and is known for featuring an image of a young woman on it. It's flexible and makes assembling/disassembling the engine and transmission much easier. Excess Gasgacinch is easy to rub away and doesn't require any solvents. The sealer bonds to a variety of surfaces, including steel, aluminum, titanium, lead, magnesium, rubber, and copper.


  • Country of Origin: USA
  • Size: 10.7 oz
  • Manufacturer Part Number: 59-9091/li>


  • Flexible sealant with a wide variety of applications
  • Impervious to other chemicals
  • Great price
  • Inexpensive price/b>
  • Cons

  • Small capacity
  • Short shelf life
  • This high-tack gasket sealant comes in a variety of sizes, including 4-ounce and 16-ounce cans as well as aerosol cans. It dries quickly, is highly tacky, and produces a non-brittle film. The product works in temperatures ranging from -65 degrees to 500 degrees Fahrenheit.


  • Country of Origin: China
  • Size: 1 lb
  • Manufacturer Part Number: 80063/li>


  • Useful for a variety of gasket-making tasks
  • Good resistance to other chemicals
  • Low price
  • Cons

  • Noxious smell
  • Messy application
  • Small can be tough to use
  • This permanent head gasket sealer stops leaks using an antifreeze-compatible sodium silicate sealing liquid and several gasket-sealing elements. The liquid technology is designed to repair damaged, leaking, and blown head gaskets. It also seals cracked cylinder heads and blocks.


  • Country of Origin: USA
  • Size: 1.5 lbs
  • Manufacturer Part Number: ‎1111
  • Pros

  • Easy to use
  • Great price
  • Takes care of multiple kinds of leaks


  • Might make coolant system blockages worse
  • May not remedy every leakage scenario
  • Our Verdict on the Best Head Gasket Sealers

    The Steel Seal Blown Head Gasket Fix Repair Sealer is our top pick for the best overall permanent head gasket sealer. It works well on older and new vehicles and is suitable for cars, vans, SUVs, and trucks. If your budget is a little tight and you still need a professional-grade sealer, check out the K-Seal ST5516 HD. It’s an affordable sealant that comes with most of the qualities you can find in more expensive brands.


    Q. Are head gasket sealers safe for the engine?

    A. Good-quality head gasket sealers are designed to work effectively without compromising the engine's function. Most sealants have been tested and known to work well with either diesel or petrol engines and with different materials such as plastic, aluminum, and cast iron.

    Q. What are some head gasket sealer tips and tricks?

    A. Make sure the product works with your antifreeze. Some head gasket sealer brands are not compatible with certain types of antifreeze. Read the instructions, and make sure it's safe to use with the antifreeze in your vehicle.

    You can either completely replace a blown head gasket or try to use a sealant to repair it. Sometimes a sealant will do the job, and sometimes you need to invest in a new head gasket. If the part is old and too damaged, a sealant will probably not correct the problem, so don’t waste your time and energy on a product that won’t likely work.

    If you think your vehicle has a blown head gasket, stop driving it. The oil will mix with the coolant, which will cause your car or truck to overheat and misfire.

    Q. What can I expect to pay for a head gasket sealer?

    A. Under $20: This price range includes head gasket sealers that come in small containers weighing under 16 ounces. The content of these containers can help you handle leakages associated with the head gasket effectively, though you might have to get a bigger container for larger engines.

    $25-$50: If you are looking for a larger container that can fix a couple of leaks, then look into products in this price range. The containers typically have 32 ounces of fluid. That’s enough to handle six- and eight-cylinder engines.

    $50 and up: In this price range, you will find premium products. These are sealers that can fix cracked head gaskets permanently and are from reputable brands. The quantity is also enough to deal with larger engines such as six-cylinder engines and more.

    Q. Are head gasket sealers better than complete gasket replacement?

    A. This depends on the level of damage you are dealing with. Most head gasket sealers provide a permanent solution to minor leakages. They will, however, only offer a temporary solution to severe leaks, and eventually, you might need a complete gasket replacement.

    Q. How long will the head gasket sealer last after application?

    A. Different brands have different qualities and while some will last long, others will not. It also depends on the severity of the damage to your head gasket. Most sealants offer permanent solutions to minor leaks but can only last for a maximum of six months if the damage is severe.

    Q. Will the sealant clog other holes in the system?

    A. Sealants are designed to fill up small holes in the head gasket. Most, however, can also clog up leaks in the transmission, power steering, and hydraulic systems. If you are dealing with bigger holes that the sealer cannot handle, you should think about replacing the head gasket. 

    Why Trust Us

    Our reviews are driven by a combination of hands-on testing, expert input, “wisdom of the crowd” assessments from actual buyers, and our own expertise. We always aim to offer genuine, accurate guides to help you find the best picks.

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