Best Gasket Sealers: Keep Fluids and Gases Inside Where They Belong

These top gasket sealers are helpful in automotive work

byMike Aguilar|
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BYMike Aguilar/ LAST UPDATED ON September 30, 2021

Gasket sealer is used when you need to seal something but it doesn’t have a gasket. Most car and truck manufacturers argue against the use of gasket sealer, largely because people often use way too much. However, there are times when gasket sealer is specified by the manufacturer (for items such as differential covers and oil pans, for example). Here are the best gasket sealers on the market.

Best Overall
Gasgacinch 440-A

Gasgacinch 440-A

Gasgacinch is one of the go-to gasket sealers for engine builders and technicians. It applies with a high tack to adhere to any surface.
The brush-on application ensures that you can’t put too much of this stuff on. It works in all conditions in automotive applications. It also works well as a belt dressing. Maintains flexibility when cured.
This product is really hard to clean off your hands without harsh chemicals.  Some buyers claim it isn’t as high quality as it used to be.
Best Value

Permatex Ultra Black

Great for use on differential housing covers, oil pans, valve covers, and any surfaces exposed to oil.
Eliminates the need for paper, cork, or rubber gaskets.  Retains sealing qualities between -65 and 500 degrees Fahrenheit.
It is easy to use too much of this product. The excess product ends up where you don’t want it: on the inside of moving parts. It’s also hard to clean up.
Honorable Mention

Permatex Aviation Form-A-Gasket

This is another go-to sealant for professionals. It dries slowly to give you time to assemble your parts, and it adheres to most surfaces.
It’s great when used to adhere to a gasket (paper, rubber, or cork) to a horizontal or vertical surface for mounting. It’s resistant to gas, oil, and most acids. Maintains flexibility when cured, even down to -65 degrees and up to 400 degrees Fahrenheit.
Fumes are really strong, so this product must be used in a ventilated space. Not terribly good for threads on fuel lines. Bottles tend to leak over time with normal use.

Benefits of Gasket Sealers

  • Extra protection against leaks. Using a gasket sealer can prevent leaks between surfaces. This is especially true for older engines where the surface may be pitted, gouged, or scraped, preventing a good seal and allowing leaks.
  • Stronger mating. When you use a gasket sealer properly, it can make a good seal even better because it can make the seal stronger. A stronger seal lasts longer and also allows parts to last longer. 
  • Sealing ability. Some applications, like oil pans and differential covers, require a gasket sealer. You don’t have to purchase a separate gasket because a gasket sealer is semi-liquid. It creates its own seal.  

Types of Gasket Sealers


Also called Indian Head (from the Permatex product), use this sealer for cardboard or thin paper gaskets in low pressure and low-temperature situations (between 300 and 350 degrees Fahrenheit). It resists motor fluids and most technicians use it to mount thermostat, differential, and timing cover gaskets. This type is easy to remove.

High Tack 

This is a non-drying gasket sealer that technicians use in situations similar to where they use shellac, but these sealers can handle temperatures up to 500 degrees Fahrenheit. High tack sealers are resistant to diesel fuel, propane, and kerosene, and they remain tacky.

Gasket Makers

These sealers come in three versions: 1) fast-hardening, fast-drying, 2) slow-drying and brushable, and 3) non-hardening. Each forms a gasket that can take temperatures up to 400 degrees Fahrenheit. Technicians use #1 to install threaded connections and block expansion plugs and to create seals between metal-to-metal flanges. They use #2 on paper or cork oil pan gaskets and neoprene transmission pan gaskets. Technicians use sealers of the #3 variety for hose connection seals. 


Technicians use this type of sealer for head gaskets and exhaust manifold. It fills tiny imperfections in metal, therefore providing a definite seal. Metal in the sealer helps to dissipate heat and promotes uniform transfer between mating surfaces. These sealers can handle as much as 500 degrees Fahrenheit and are used for exhaust and cylinder head gaskets. They are easy to remove even long after installation. 


These sealers are typically marketed in a tube and are red in color. Technicians use them where an external air source is unavailable to assist in drying. Manufacturers developed them to satisfy OEM needs for non-corrosive gasket creators in metal-to-metal situations. They’re used in situations where a replacement is not available or where there never was a gasket. 

RTV Silicone

RTV and Ultra RTV silicone sealers (room temperature vulcanizing, i.e., the temperature when the silicone begins to set up) work in situations up to 750 degrees Fahrenheit. You can find these in multiple colors and in various depending modes: aerosol cans, tubes, and caulk-gun style cartridges. The color of the sealer indicates heat tolerance. Gray, black, and blue are for up to 500 degrees; red and orange are for up to 650 degrees, and copper is for up to 750 degrees. Experts recommend using the Ultra version for the current electronically-controlled vehicles because they are safe for sensors. 

Top Brands


Founded in the United States, Gasgacinch has been creating and marketing gasket sealers for more than 50 years. The company’s iconic “slipping girl” mascot is based on World War II pinup girl art and is recognized worldwide. The mascot’s design dates from the 1950s. Gasgacinch makes gasket sealers for standard auto and truck applications but also has products for specialty vehicles like high-performance cars and for motorcycles. Popular products include the 440C Gasket Sealer and Belt Dressing and the 440-B Gasket Sealer and Belt Dressing


Beginning in 1909, when company founder Constant Benolt, Sr. developed the first Permatex product, a sealer for bicycle tires, the company has been manufacturing, marketing, and distributing its gasket sealers in the United States. With locations in New York, Kansas City, and Florida, the company moved to Cleveland, Ohio in the 1970s after the Loctite Corporation bought it. In 2005, ITW (Illinois Tool Works) bought Permatex, the present owner and parent company. Check out popular Permatex gasket sealers like its Gear Oil Gasket Maker and High Temp Red RTV Silicone Gasket Maker.

Gasket Sealer Pricing

  • Under $10. Economical yet effective sealers occupy this price range. It starts at the low price end with silicone sealers for water pumps and thermostat housings and includes silicone gasket makers at the $10 end.
  • $10-$20. This price range includes elastometric rubber and silicone gasket makers that replace rubber, paper, and cork gaskets. You get varied amounts for your purchase, from 1.7 ounces to 5 ounces, depending on the product.
  • $20-$90. In this price range, you’ll find gasket sealers for permanent head gasket and engine block repair, including effectively sealing cracks in head gaskets. These sealers provide extra-strong, durable repair and come in pourable and aerosol can versions. 

Key Features


A sealer helps strengthen a gasket. It works in conjunction with the gasket as opposed to creating its own gasket. A sealer fills porous areas, gouges, and scrapes in metal and other materials so no liquid or gas can escape and the gasket itself can work better. A product that works with a gasket seals the area better. This allows parts to do their job and assemblies to operate more efficiently. 

Gasket Creator

This type of product creates a gasket where you need one. After you apply it to a surface, it forms a gasket where there wasn’t one before. This saves you from having to purchase (or make your own) gasket. When you apply it and it sets up, it does the same job as a paper, fiber, or composite gasket. 

Surface Mater

This type of gasket mates surfaces, much like glue or an adhesive. This gasket type does two jobs: It forms a seal but also adheres to the two surfaces together, so they function as one part or assembly. Because it forms a seal, no gases or liquids can leak. Because it works like an adhesive, the parts you want to work together mate so they can work together. 

Other Considerations

  • Type of Sealer. The type of gasket sealer you buy obviously depends on your need and the application. If you’re reinforcing a gasket with a sealer, it’s an entirely different situation than if you need to create a gasket. Similarly, if you need to mate two surfaces together, the sealer you buy must have this capability.
  • Temperature. Some silicone gasket sealers are rated only up to 300 degrees Fahrenheit. Others are formulated to withstand temperatures of up to 750 degrees. Using a gasket sealer for a water pump or thermostat housing does not require high heat properties like a sealer for an exhaust manifold. 
  • Type of Dispenser. Beyond convenience, the type of dispenser for the gasket sealer not only depends on the application but also on the type of material you’re working with (metal, plastic, etc.) and the work area and work surface itself. The surface may be pitted or gouged, so your sealer must address this, and the work area such as an engine compartment may not allow you enough room to use an aerosol spray can for delivery.

Best Gasket Sealer Reviews & Recommendations 2021

A preferred gasket sealer used by technicians worldwide, this sealer adheres to any surface, is high tack, and remains flexible after it cures. The sealer works in all sealing and gasket situations, from water pumps to exhaust headers. It’s good for work on cars, SUVs, and trucks, diesel, gas, and electric motors, as well as transmissions and trim.

However, take care not to get the gasket sealer on your hands. Wear flexible gloves when working with it because some users report that the gasket sealer is difficult to remove without using strong chemicals. Also, there have been some reports of the product’s reduced quality compared to earlier years.

This sealer is safe for use around sensors. It is non-corrosive, long-lasting, and adheres well to oily parts. It resists many powertrain liquids like gear lube, engine oil, coolants, and transmission fluid. The sealer is highly flexible and does away with the need for pre-cut or pre-formed cork, rubber, and paper gaskets. It works for oil pan applications and valve, differential, and timing covers. It also maintains sealing abilities from -65 to 500 degrees Fahrenheit. 

However, be careful when dispensing the product. It flows out easily and, therefore, you can easily squeeze out too much and it may end up where you don’t want it, like on the inside of moving components. Some report that it is difficult to clean up.

This gasket sealer from Permatex is slow drying to allow you to assemble your parts. It works well for adhering cork, paper, or rubber gaskets to vertical or horizontal surfaces. It resists grease, gas, and oil. You can use it on multiple aviation and automotive applications such as solid gaskets, on tight-fitting machined surfaces, and for sealing hoses. 

Caution: Use this gasket sealer in a well-ventilated area because the fumes from this sealer are very strong. Keep in mind that it does not work very well for threads on fuel lines. Also, some users report that the bottle may leak.

Permatex has several sealers on the market, and The Right Stuff is geared towards automotive use. It efficiently works on components such as water pumps, oil pans, thermostat housings, and gearbox and valve covers. The product has a continuous temperature range of minus 75 to 450 degrees Fahrenheit with an intermittent range of 500 degrees. The Right Stuff creates an instant, durable, and leakproof seal by creating an elastomeric rubber gasket. The sealer resists blowouts and prevents leaks and seepage due to thermal expansion and vibration. It cures quickly, and it produces a seal that is somewhat soft but tough and solvent-resistant.

One downside with this product is it's very messy, and it can also be challenging to extract from the tube. As a result, you may have to use a regular caulking tube to use it. There have also been some complaints that the nozzle breaks, making it difficult to get access to the sealer.

Many automotive manufacturers and Formula 1 teams use this non-setting and non-hardening gasket sealer. It is designed for sealing gaps up to 0.25 mm and for dressing gaskets and threads. The product is vibration-resistant and can withstand severe changes in temperature. Hylomar Blue is resistant to fluids such as engine coolant, petroleum, lubricating oils, and water. A little bit of Hylomar goes a long way. It creates a leak-proof seal and is one of the best all-purpose, non-hardening gasket sealers on the market. Since it doesn't completely harden, it's ideal when you need to seal a joint that has coolant or oil passing through it. For example, you can use it to seal camshaft caps on overhead cam engines. If you want to keep oil in and everything else out, this is the perfect product.

There are just a couple downsides to this gasket sealer. It may separate over time if you leave it sitting in your toolbox. Also, it's a tough and sticky substance, and if you put it on the gasket and the surface and need to remove it, there's a good chance you will ruin the gasket material.

Designed specifically for automotive engines, this gasket sealer from 3M cures rapidly in place and is flexible and non-corrosive. It can withstand intermittent temperatures up to 600-degrees Fahrenheit, is oxygen sensor safe, and resists water, oil, and ethylene glycol. You can use it as a gasket dressing or gasket alternative. The product comes in a 3-ounce tube.3M High Temp Silicone Gasket sealer can be used on intake manifolds, oil and transmission pans, timing chain covers, thermostat housings, and valve covers. It is easy to use by simply applying it to a clean and prepped surface area, and you can start the engine 15 minutes after application. Subaru specifies this sealer as a replacement for its OEM sealant.

The biggest complaint about this product is that if you don't use the whole tube at once, it has a tendency to dry out and can harden after a few months in storage. Also, it doesn't come with a graduated dispensing tube, which would make it easier to use.

Bar’s Leaks Head Gasket Repair is designed to tackle coolant leaks. It features a combination of aramid and refractory fibers that make it strong and heat-resistant. It penetrates leaks and forms a seal that is tougher than the original head gasket. The product is ideal for repairing blown head gaskets, stopping block leaks, and sealing cracked cylinder heads. This gasket sealer works as advertised. It stops leaks immediately, and the repair lasts for a long time as long as you follow the directions precisely. Some users report that their engines run a lot better after using this product and that the engines are smoother and no longer hesitate. In addition, this sealer is a little less expensive than some comparable products.

However, Bar's Leaks 1100 Head Gasket Repair is not compatible with antifreeze, and you must use it only after flushing and removing antifreeze from the cooling system, which can be a lengthy process. If you don't follow the process correctly, you can experience clogging issues.

Three Bond Engine Silicone Gasket 1211 is a semi-hardening sealer that is tough and durable. It uses silicone rubber and comes in a 3.5-ounce tube. It's designed for use on gaskets, crank seals, case matting surfaces, and more. It's tack-free within 90 minutes and cures in 24 hours. The product is comparable to yamabond and hondabond and can be used for both motorcycle and automotive purposes. It is thicker than Permatex Aviation and is easy to apply and clean up. It's great for everything from sealing engine cases and gaskets to sealing a timing chain cover or lawnmower case cover. A little bit goes a long way, and it has a metal tip cleaner to clean out the application tip so you can easily reuse it.

However, it takes a while to dry, and it's a little pricey. In addition, the sealer is white, which may not be the best option when it comes to aesthetics.


  • Rarely do auto manufacturers recommend using a silicone- or latex-based liquid sealant by itself. Those that do insist that only a small amount be used.
  • When using a squeeze-tube type of gasket sealer, only use what you need. Don’t glob it on and wipe off the excess. Otherwise, you’ll be picking chunks of it out of your oil.
  • Liquid brush-on gasket adhesives are recommended by manufacturers for transmission oil pans since latex or silicone sealers can break off and clog vital orifices, damaging your transmission.
  • When using a gasket sealer on exhaust components, pick one with a high copper content to resist the high temperatures in exhaust systems.
  • Whether you use a gasket sealer or not, remove as much of the old gasket as possible without scraping or scratching the mating surfaces. If you don’t get all the old material off, especially out of grooves, or if you scratch the surface, you will cause leaks instead of sealing them.


Q: What is the difference between a gasket adhesive and a gasket sealer?

A: A gasket sealer is the gooey, gloppy stuff every one associates with gasket sealing. Gasket adhesive is more of an extra-strength contact cement with properties that make it chemically resistant.

Q: Why use gasket adhesive or sealer when my part comes with a gasket?

A: Good question. Except in certain circumstances, a gasket sealer is used as nothing more than an adhesive. It’s there to keep the gasket from slipping during installation.

Q: My new oil pan didn’t come with a gasket. What should I use to seal it?

A: When using in place of an actual gasket, run a small bead of silicone or latex gasket sealer around the edge of the pan outside the bolt holes. Your bead should not be larger than 1/8 inch in width/diameter. Excess gasket sealer can actually cause leakage.

Final Thoughts

Our choice for the best overall gasket sealer, Gasgacinch 440-A, is the choice of professional race engine builders.

Our pick for the best value gasket sealer, Permatex Ultra Black, is a great choice for those times when you don’t have a paper, cork, or rubber gasket and you’re putting parts together that will be subjected to a lot of oil when in use.

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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