Best Gasket Sealers: Keep Fluids and Gases Inside Where They Belong
These top gasket sealers are helpful in automotive work
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BY Mike Aguilar / LAST UPDATED ON November 27, 2019
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.
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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.
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.
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 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.
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.
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.
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.
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.
- 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
- 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.
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.