Do paper seals need sealant? (2023)

Gaskets play a key role in your engine's performance. They prevent dirt, dust, gases and liquids from escaping and damaging your engine. This is possible by creating a barrier between two surfaces or parts.

Using the correct type of gasket and sealer will ensure a long lasting seal. However, there is still the dilemma of whether paper gaskets require sealant. In this article, you'll learn about the benefits of using sealants and common mistakes that could compromise the integrity of your gasket.

What is a paper stamp?

A paper gasket is a large piece of sheet metal used to make a sealant or sealant to join components or surfaces. Contrary to its name, it consists of flexible and robust materials such as cork, nitrile or silicone rubber. In addition, paper seals are a quick and inexpensive way to seal.

A gasket is a small piece of sheet metal cut from the sealing material. It is often cut into an O-ring shape to create a compressible, leak-proof seal between the two components. In addition, paper seals are available in a variety of shapes and sizes, making them suitable for a variety of applications. For this reason, they are named according to their purpose. Vehicle seals are designed for use in car engines, for example.

Now that we know what paper gaskets are, let's look at some of the types available and see if they require a sealant.

Which paper seals are good?

  1. Gummidichtungsplatte
  2. Cork sealing sheet
  3. Silicone sealing plates
  4. Nitrile sealing plates
  5. Graphite sealing plates
  6. asbestos sealing plates
  7. Sealing plates for high temperatures
  8. exhaust sealing plates

Types of paper seals

Since there are different types of paper sealants on the market, it is important to familiarize yourself with the most common types.

1. Gummidichtungsplatte

This is an entry-level, versatile sealing material that offers protection against gas leaks. You can also use it to treat alkalis or mild acids. However, because it is made of rubber, its rubbery properties make it unsuitable for high pressure/high temperature and oil applications.

2. Cork sealing sheet

Cork gaskets are easy to compress and are very good for fuels, oils and solvents. This is because they do not react aggressively when they come into contact with said substances. However, although these panels offer excellent vibration dampening properties, they lack mechanical strength, particularly in the torso and flex areas.

3. Silicone sealing plates

They are excellent for use outdoors or in places where moisture is present. Because they are temperature resistant, flexible and have water resistance properties. However, these boards are not only electrically insulating, they are also unsuitable for vapors and oils.

4. Nitrile sealing plates

They are versatile and offer a wide range of uses, for example to protect against oil and water leaks, silicone grease and hydrocarbons. In addition, these panels offer excellent performance at high temperatures. However, in addition to being resistant to chemicals, it is also not suitable for handling chlorine, ketones and other oxidants.

5. Graphite sealing plates

They have a wide range of applications, including high pressure and high temperature environments. The flexibility of graphite sheets depends on the concentration of carbon content. However, this also makes the panels brittle and requires fillers or metal cores for reinforcement.

6. Asbestos sealing plates

They are made of fibrous and robust material that can withstand extreme temperatures and chemicals. However, working near these panels carries a dangerous risk.

7. High temperature sealing plates

High temperatures affect how compressible and flexible the sealing plate is. It therefore becomes a challenge for high-temperature plates, which are more brittle and unsuitable for high-vibration applications. Additionally, you cannot use these panels in applications that require full leakage control.

8. Exhaust system gasket sheets

Designed for use in exhaust systems, ventilation systems and machinery, these panels can withstand high temperatures for long periods without failure. In addition, they are gas-tight and easy to clean and maintain.

Is it common for paper seals to fail?

Seals are designed to prevent dirt, dust, liquids, static electricity and gases from affecting the performance and functionality of your engine. However, if the paper seals are not properly installed and sealed, they can fail. A good indicator of failure is loss of coolant, whether or not there are signs of a leak.

Other possible indicators include engine overheating, cylinder misfiring, and the check engine light on the dashboard. Additionally, a gasket failure can allow gases, coolant, and other materials to damage and destroy your engine.

Improper installation is often the cause of gasket failure. In addition, the use of the wrong couplings or an improper procedure can lead to uneven clamping and thus to leakage. To prevent this, sealants are used.

Do paper seals need sealant?

Sealants are useful when used during sealant placement. Benefits include:

  • The sealing gasket provides additional protection against leakage. Holes or gaps between surfaces can create space for dust, solvents or gases to enter or exit. Gasket sealants ensure that the gaps between surfaces are filled to prevent leakage.
  • Sealants strengthen the connection between two surfaces. Therefore, when used properly, the sealant becomes stronger and can last longer. In addition, this also increases the longevity of the sealed parts.
  • Sealing applications such as oil handling or differential covers require a sealer for added protection. This improves the tightness and ensures that there are no leaks.

types of sealants

1. Shellac sealant for gaskets

Also known as Indian head shellac, this sealant works best with thin paper or cardboard gaskets. It is suitable for low temperatures between 300 and 350 degrees Fahrenheit and low pressure use. In addition, this sealant is popular among technicians because it is resistant to engine fluids and is easy to remove. That's why you can use it to mount thermostats for timing cover gaskets and differentials.

2. Sealing gasket with high adhesive strength

Similar to shellac sealants, high tack sealants are resistant to propane, diesel and kerosene. In addition, they can withstand high temperatures of up to 500 degrees Fahrenheit. Highly tacky sealants do not dry and remain tacky after application.

3. Sealant manufacturer

Sealing machines come in three different shapes, each with a temperature capability of 400°F. The first form is fast hardening and fast drying. Its purpose is to install threaded connections, thereby blocking expansion plugs. In addition, you can use it to seal between two metals.

The second form dries slowly and can be spread. You can use it for a cork oil pan or for paper seals and neoprene gear pan seals. Finally, non-curing gasket markers are mainly used to place gaskets on hose connections.

4. Sealant for copper seals

You can use copper sealant to fill gaps in metals such as exhaust manifolds and head gaskets. This ensures a secure seal, helps distribute heat and promotes even transfer between the mating components. Their application in cylinder head gaskets is especially important because copper gaskets can withstand temperatures up to 500°F. In addition, they can be easily removed even a long time after installation.

5. Anaerober Version geller

This type of seal is particularly applicable when there is no external air source to aid drying. To distinguish them from others, anaerobic closures are in tubes and are colored red. In addition, they are non-corrosive and can be used in situations where a replacement is not available or a seal is not available.

6. RTV silicone sealant for sealing

Room temperature vulcanizing silicone sealants are used at high temperatures up to 750°F. They come in various colors that indicate the level of heat resistance. For example, black, gray, and blue are up to 500°F, while orange and red are up to 650°F. Additionally, copper is hot up to 750°F. Ultra RTV and RTV silicone sealants are available in tubes, cartridges and aerosol cans.

What are the most common sealing mistakes?

1. Incomplete surface preparation

Before starting the assembly, it is necessary to fully prepare the surface on which you intend to work. Glue, old seals and glue are removed from the metal and the surface is cleaned. If this is not done, the mating surfaces will not align evenly.

It is not recommended to use razor blades or anything else that can scratch the metal surface. This is because scratches can be a vehicle or channel for gases and liquids to escape. Therefore, it is best to use a chemical cleaner or a nylon or plastic brush/scraper.

2. Applying the wrong amount of sealant

Determining the right amount of sealant requires a little experimentation and experience. However, if you apply too much or too little, you will get unwanted results. The excess sealing ring is squeezed out during assembly and migrates to other parts. This in turn leads to clogging of engine parts such as the oil pan.

On the other hand, a small amount of sealant will result in insufficient sealing. To get the perfect amount, apply the sealant in a continuous, even bead about 1/8 inch thick. This ensures that the sealant spreads in a thin layer that is compacted during installation. Also, circle all screw holes as you apply.

3. Using the wrong type of gasket manufacturer

Manufacturers of flange gaskets and gaskets are designed for different applications. For example, some have resistance to high temperatures, while others protect against certain leaks. Using one flange sealant for different applications will not provide the desired performance. So make sure the sealant you use meets the specific needs of your application.

4. Using a manufacturer's gasket instead of a traditional gasket

This is a common mistake that technicians make. It is not recommended to use the device to make a sealant as a preparation for a standard gasket. This is because the sealant formulation is too thick to be used as a dressing. Consequences include void formation, seal damage, and the need for resealing. In addition, there are sealants in the form of liquids, sprays and tubes that you can use when installing a standard gasket.

5. Filling large gaps with anaerobic sealing machines

The anaerobic caulking machine is designed to fill small holes or voids between 15 and 20 mil in size. If you have larger voids that need to be filled, it is best to use the sealant manufacturer's RTV. This is because RTV sealants have a tighter seal and no air pockets.

6. Insufficient curing time

When working with a solvent-based flange sealant, it is advisable to give it sufficient time to cure or dry. If you don't wait for it to finish curing, you will compromise the integrity of your seal. For example, seal manufacturers using solvent-based materials must air dry completely before assembly and allow an additional 10 minutes before rechecking the torque.

When working with RTVs, you will need about 2 hours to build and 24 hours to fully cure. However, there are formulas for making seals that allow torque and Go. This means that you can, for example, immediately put your car into operation without planning a repair time.

7. Allow solvent-free sealants to partially dry before assembly

While sealant manufacturers are generally believed to require curing prior to assembly, this is not the case with solvent-free alternatives. Most sealants work best when installed immediately wet. However, the exception is sealants that contain solvents. For example, the curing of anaerobic sealants does not begin until after assembly. This is because they do not need oxygen to dry.

8. Head gasket replacement by the gasket manufacturer

Although most flange gaskets can replace standard and cast gaskets, head gaskets should never be replaced by the gasket manufacturer. When looking for a replacement cylinder head, always stick with the typical OE gaskets instead.

9. Quick assembly

Hasty installation means incomplete curing time. This is a common mistake that most technicians make. While sealants allow immediate installation, others require a drying time of at least 24 hours before installation. Whether you're a DIYer or a technician, check the required drying time of the manufacturer of the sealant you're using to avoid rushing the assembly process.

10. Replace only one gasket

Most people make the mistake of changing the gasket rather than the whole set. This practice increases the likelihood of further gasket failures in the future. It is best to install all parts at once with new gaskets.

Other mistakes to avoid are:

  • Application of anaerobic or RTV flange sealant to surfaces exposed to gasoline
  • Using head gaskets that are cheaper than recommended
  • Using the wrong gasket material
  • Improper use of sealant


A quality and long-lasting seal is determined by the seal and sealant used during installation. While many technicians mistakenly believe that a gasket by itself provides a proper seal, using a flange sealant can save you money and time. In addition, by researching your application project and avoiding mistakes, you save valuable time during installation.


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