Do Paper Gaskets Need Sealant?

do paper gaskets need sealant

Gaskets play an essential role in the performance of your engine. They prevent dirt, dust, gasses and fluids from leaking and harming your engine. This is made possible by creating a barrier between the two surfaces or parts.

Using the right type of gasket and sealant ensures that you have a durable seal. However, it is still a dilemma whether paper gaskets need sealant. This article will shed some light on the benefits of using a gasket sealant and common mistakes that could compromise the integrity of your seal.

What Is A Paper Gasket?

A paper gasket is a large sheeting piece used in making gaskets or seals to join components or surfaces together. Contrary to its name, it is made of flexible and robust materials, such as cork, nitrile, or silicon rubber. In addition, paper gaskets are a quick and cost-effective way of making a seal.

A gasket is a small piece of sheet cut from the gasket material. It is often cut in an O-ring shape to form a compressible leak-proof seal between two components. In addition, paper gaskets are available in different shapes and sizes, making them ideal for various uses. For this reason, they are named after their intended use. Vehicle gaskets, for example, are designed to be used in car engines.

Now that we know what paper gaskets are, let us look at some of the available types and whether they need sealants.

Which is a good Paper Gaskets?

Types of Paper Gaskets

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

1. Rubber Gasket Sheet

This is an all-rounder entry-level gasket material that offers protection against gas leaks. You can also use it to deal with alkali or mild acids. However, since it is made of rubber, the rubber properties render it unsuitable for high pressure/temperature and oils application.

2. Cork Gasket Sheet

Cork gaskets are easy to compress and very suitable for fuels, oils and solvents. This is because they do not have an aggressive reaction when in contact with the named substances. However, although these sheets offer outstanding vibration-damping properties, they lack mechanical strength, especially under torso and flex.

3. Silicone Gasket Sheets

These make a suitable choice for use in an outdoor environment or in places where moisture is present. This is because they are temperature resistant, flexible and have waterproofing properties. However, besides having electrical insulation properties, these sheets are not suitable for steams and oils.

4. Nitrile Gasket Sheets

These are versatile and offer a wide range of uses, such as protection against oil and water leaks, silicon greases and hydrocarbons. In addition, these sheets provide excellent performance under high temperatures. However, besides being chemical resistant, it is unsuitable for handling chlorines, ketones and other oxidizing agents.

5. Graphite Gasket Sheets

They have a wide range of applications, including in high pressure and temperature environments. The flexibility of graphite sheets relies on the concentration of carbon content. However, this also makes the sheets brittle and will need fillers or metal cores to offer reinforcement.

6. Asbestos Gasket Sheets

These are made from a fibrous and tough material that offers resistance to extreme temperatures and chemicals. However, working close to these sheets poses a hazardous risk.

7. High-Temperature Gasket Sheets

High temperature affects how compressible and flexible a gasket sheet is. Therefore, it becomes a challenge for high-temperature sheets since they are more brittle and unsuitable for applications with high vibrations. In addition, you cannot use these sheets in applications requiring complete leakage control.

8. Exhaust Gasket Sheets

Designed for application in extraction systems, venting and machinery, these sheets have the ability to withstand high temperatures for long periods without failing. In addition, they are gas leak-resistant, easy to clean and maintain.

Is It Common For Paper Gaskets to Fail?

Gaskets are meant to prevent dirt, dust, fluids, electrostatic charges and gases from limiting the performance and functionality of your engine. However, when not properly installed and sealed, paper gaskets can fail. A good indicator of failure is losing coolant, whether or not there are signs of a leak.

Other possible indicators include your engine heating, misfire in your cylinders and a check engine light activating on your dashboard. In addition, gasket failure could result in gases, coolants and other materials harming and destroying your engine.

Poor installation is often to blame for gasket failure. In addition, if the wrong type of fasteners are used or the procedure used is not fit, uneven clamping resulting in a leak may occur. Gasket sealants are used to prevent this.

Do Paper Gaskets Need Sealant?

Gasket sealers are beneficial when used during a gasket installation. Some of the benefits include:

  • A gasket sealer offers extra protection against leaks. Holes or gaps between surfaces could create spaces for dust, solvents, or gases to get in or out. Gasket sealers ensure that the gaps between surfaces are filled to prevent leaks.
  • Gasket sealants strengthen the mating between two surfaces. Therefore, when used well, the seal becomes stronger and can last longer too. In addition, this also increases the longevity of the sealed parts.
  • Gasket applications, such as when dealing with oils or differential covers, will require a sealant for added protection. This enhances the sealing ability and ensures no leaks are present.

Types of Gasket Sealers

1. Shellac Gasket Sealer

Also known as Indian head shellac, this sealant is best used for thin paper gaskets or cardboards. It is good for low temperatures between 300 and 350 degrees Fahrenheit and low-pressure usage. In addition, this gasket sealant is a favorite among technicians since it is resistant to motor fluids and easy to remove. For this reason, you can use it to mount a thermostat for timing cover gaskets and differentials.

2. High Tack Gasket Sealer

Similar to shellac gasket sealers, high tack sealants are resistant to propane, diesel and kerosene. In addition, they can handle high temperatures of up to 500 degrees Fahrenheit. High tack sealants are non-drying and remain tacky after application.

3. Gasket Makers

Gasket makers come in three different forms, each of which is has a temperature capacity of 400°F. The first form is fast hardening and fast drying. Its purpose is to install threaded connections hence blocking expansion plugs. In addition, you can use it to create seals between two metals.

The second form is slow drying and brushable. You can use it on a cork oil pan or paper gaskets and neoprene transmission pan gaskets. Finally, non-hardening gasket markers are mostly used to add seals to hose connections.

4. Copper Gasket Sealer

You can use copper gasket sealers to fill gaps in metals, such as exhaust manifolds and cylinder head gaskets. This gives a definite seal, helps to distribute heat and promotes even transfers between mating components. Their application in a cylinder head gasket is especially because copper sealants can handle up to 500°F. In addition, they are easy to remove even long periods after installation.

5. Anaerobic Sealer

This type of sealer is mostly applicable when there is no external air source to support drying. To differentiate them from others, anaerobic sealers will be in tubes and are red in color. In addition, they are non-corrosive and can be applied in scenarios where no replacement is available or no gasket is present.

6. RTV Silicone Gasket Sealer

Room temperature vulcanizing silicone sealers are used under high temperatures of up to 750°F. They come in varying colors, which indicate the level of heat tolerance. For example, black, grey and blue are up to 500°F, while orange and red are up to 650°F. In addition, copper is up to 750°F. Ultra RTV and RTV silicone gasket sealers are available in tubes, caulk-gun style cartridges and aerosol cans.

What Are the Most Common Mistakes During Gasketing?

1. Incomplete Surface Preparation

Before beginning installation, it is imperative that you fully prepare the surface you will be working on. This involves removing glue, old gaskets and adhesives present on the metal and cleaning the surface. Failure to do this results in mating surfaces that are not evenly aligned.

Using a razor blade or anything that can scratch the metal surface is not advised. This is because scratches may provide a means or a channel for gases and fluids to leak through. Therefore, it is best to use a chemical cleaner or a brush/scrapper made of nylon or plastic.

2. Applying the Wrong Sealant Amount

Knowing the right amount of sealant to apply takes a few trials and errors and experience. However, applying too much or too little will give you undesired results. The excess gasket maker squeezes out and moves to other parts during assembly. In turn, this causes clogging on engine parts like the oil pickup.

On the other hand, applying little sealant results in an insufficient seal. To get the perfect amount, apply the gasket maker in one continuous even bead about 1/8” thick. This ensures that the sealant spreads into a thin layer that tightens up during assembly. In addition, ensure that you circle all bolt holes during application.

3. Applying the Wrong Type of Gasket Maker

Flange sealants and gasket makers are designed to fit different uses. For example, some have high-temperature resistance, while others protect against specific leaks. Using one flange sealant for different applications will not give the desired performance. Therefore, ensure that the gasket sealer you are using meets the specific needs for your application.

4. Using a Gasket Maker in place of A Conventional Gasket

This is a common error that technicians make. Using a gasket maker as gasket dressing for a standard gasket is not recommended. This is because the formulation of a gasket sealer is too thick to be used as a dressing. The effects include creating gaps, ruining the seal and having to re-install the gaskets. In addition, there are gasket sealers available in liquids, sprays and tubes to use when installing a standard gasket.

5. Filling Large Gaps With Anaerobic Gasket Makers

An anaerobic gasket maker is designed to fill small holes or gaps ranging between 15-20 thousandths of an inch. If you have larger gaps that need filling, it is best to use an RTV gasket maker. This is because RTV sealants have a tighter seal with no air pockets present.

6. Insufficient Curing Time

When working with a solvent-based flange sealant, it is recommended to give it ample time to cure or dry. Failure to wait for curing to complete compromises the integrity of your seal. For example, solvent-based gasket makers need to completely air dry before reassembling and an additional 10 minutes before rechecking torque.

When working with RTVs, you need about 2 hours to set up and 24 hours for a full cure to be achieved. However, there are gasket maker formulas that allow for torque and go. This means that you can put back, your car for example, in service immediately without allocating a cure time.

7. Allowing Non-Solvent Gasket Makers to Partially Dry Before Assembly

While it is a common assumption that gasket makers need to cure before assembling, this is not the case with the non-solvent alternatives. Most gasket sealers work best when assembled immediately when wet. However, solvent-based sealants are an exception to this rule. For example, anaerobic sealants won't begin to cure until after assembling. This is because they do not need oxygen to dry.

8. Replacing A Head Gasket with A Gasket Maker

While most flange sealants can replace standard and formed gaskets, you should never replace head gaskets with a gasket maker. Instead, always stick to the typical OE-style gaskets when looking for a cylinder head replacement.

9. Rushed Assembly

Rushed assembly means incomplete curing time. This is a common mistake that most technicians make. While sealants allow for immediate assembly, others need at least 24 hours of drying time before assembly. Whether you are a DIYer or a technician, confirm the required drying time of the gasket maker you are using to prevent rushing into the assembling process.

10. Replacing Only One Gasket

Most people make the mistake of replacing one gasket rather than the complete set. This practice increases the chances of additional gasket failure in the future. It is best to apply new gaskets to all the parts in one go.

Other Mistakes to Avoid Include:

  • Applying anaerobic or RTV flange sealant on surfaces exposed to gasoline
  • Using head gaskets that are less expensive than recommended
  • Using the wrong material for the gasket
  • Improper use of a sealer


A quality and durable seal is determined by the gasket and sealant used during installation. While many technicians erroneously believe that a gasket alone provides enough seal, using a flange sealant will save you money and time. In addition, researching your application project and avoiding mistakes will ensure that you have quality time during installation.

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