What are valve cover gaskets made of?

Valve cover gaskets are usually made from rubber-based compounds, often EPDM or nitrile, with silicone gaining popularity in newer designs; cork and graphite composites also appear, depending on the engine. The exact material varies by manufacturer and application.

In modern engines, material choices are driven by heat exposure, oil compatibility, durability, and cost. While older vehicles commonly used cork-rubber blends, today many engineers favor silicone or graphite-based seals for longer life and better resistance to oil and high temperatures. Below is a look at the main material families you’ll encounter and what they’re typically used for.

Materials commonly used in valve cover gaskets

The following list outlines the primary gasket material families and why manufacturers choose them.

• Rubber-based gaskets (EPDM or nitrile/NBR), often with a metal or polymer backing to provide rigidity and crush resistance.


• Silicone rubber gaskets, prized for high-temperature tolerance, oil resistance, and long service life.


• Cork-based gaskets, typically compressed cork bound with rubber for flexibility and cost-effectiveness, common on older or budget vehicles.


• Graphite or graphite-impregnated composites, offering excellent heat and oil resistance and good resilience, used on many modern engines.


• Composite or reinforced designs (including metal-backed or multi-layer rubber/graphite configurations) that blend materials to balance durability and sealing force.

In practice, the best choice is the gasket specified by the vehicle’s manufacturer; aftermarket options mimic these materials, but compatibility with your engine design and cover profile matters.

Performance implications and maintenance considerations

Material choice impacts heat tolerance, oil compatibility, seal longevity, and install practicalities. Silicone gaskets tend to perform well under higher temperatures and offer longer lifespans but can cost more. Cork blends are economical and forgiving but may wear faster in high-mileage or high-heat applications. Graphite-based gaskets strike a balance between heat resistance and durability and are common in many modern engines. Always prefer OEM-recommended materials or trusted aftermarket equivalents designed for your specific engine to ensure a reliable seal.

Maintenance and replacement tips

When replacing a valve cover gasket, use the correct material specified for your engine, clean the mating surfaces thoroughly, and follow torque specifications to avoid leaks. Some designs require a sealant in particular areas; others are designed to seal without sealant. Replacing the bolts with new ones and checking for oil seepage after a test run are prudent steps.

Summary

Valve cover gaskets are built from a range of materials, with rubber-based compounds (EPDM or NBR), silicone, cork, and graphite being the most common. Some designs use reinforced or composite structures that combine multiple materials for improved durability and sealing performance. The right choice depends on engine design, operating temperature, oil exposure, and manufacturer specifications. Always refer to the OEM guidance or trusted aftermarket options tailored to your vehicle to ensure a reliable seal.

What material is best for valve cover gaskets?

The best valve cover gasket material depends on the application, with FKM (Fluoroelastomer) being a top choice for its heat and chemical resistance. For street and performance engines, composite and modern rubber/silicone gaskets with features like built-in torque limiters are highly recommended for longevity and leak prevention, often surpassing traditional materials like cork. 
This video explains how to choose the right gasket for your engine: 59sSummit RacingYouTube · Apr 18, 2025
Top material recommendations

• FKM (Fluoroelastomer): Considered one of the best materials due to its exceptional high-temperature stability (up to 250°C/482°F250 °C / 482 °F250°C/482°F) and resistance to synthetic oils and fuels. 
• Modern Composite/Molded Silicone: These are high-end options that combine materials like silicone with a steel core and compression limiters to prevent over-torquing. They are very durable and offer excellent sealing. 
• Modern Rubber/Cork-Rubber: Modern blue rubber gaskets, such as some by Fel-Pro, are a significant upgrade from traditional cork. They combine the compressibility of cork with the durability of rubber, often featuring built-in torque limiters and requiring no sealant. 

You can watch this video to see how cork-rubber gaskets work: 47sPete's GarageYouTube · Oct 20, 2022
Traditional materials

• Cork: A classic material, but can dry out and shrink over time. It seals well on rougher surfaces but is prone to leaks once it's oil-soaked and dried out.
• Traditional Rubber: Can be effective, but some types may not conform as well to rough surfaces compared to cork. 

What to consider

• Application: For high-performance or racing engines, composite materials with high torque retention are ideal. For stock street engines, modern rubber or composite gaskets are often the best choice for long-term reliability.
• Reusability: Modern rubber and composite gaskets with built-in torque limiters are not designed to be reused, as the sealing bead takes a set.
• Installation: Always follow the manufacturer's instructions. For example, many modern rubber and composite gaskets are designed to be installed dry without RTV sealant, which can cause them to fail. 

This video demonstrates how to install a specific type of valve cover gasket: 59sPNW Car Mods & MaintenanceYouTube · Nov 29, 2024

What can I use to make a homemade gasket?

You can create a DIY gasket from various materials, including purpose-built gasket paper, cereal box cardboard for low-heat applications, or self-adhesive cork sheet for non-engine jobs. To make the gasket, trace the shape of the mating surface, cut it out with a sharp knife, and use a nut and bolt to punch bolt holes. Gasket sealant or dressing can be added to improve the seal, especially when using makeshift materials. 
Materials

• Gasket paper: Available at auto parts stores, it's designed for specific applications like oil or high heat resistance. 
• Cardboard: Use flat, sturdy cardboard from cereal boxes or similar packaging for low-temperature uses. 
• Self-adhesive cork: Found in craft or home improvement stores, it's a good option for projects like valve covers. 
• Neoprene or other sheet rubber: Look for rolls or sheets, sometimes with adhesive backing, at hardware or auto parts stores. 
• Other options: Compressed non-asbestos fiber, silicone, and even EPDM roll roofing scraps can work depending on the application. 

This video demonstrates how to make a cardboard gasket: 1m4DIYersYouTube · Oct 30, 2015
Steps

1. Create a template: Clean the mating surface. For a precise outline, press the surface onto the gasket material and use an oil or marker to create an impression, or trace around the part. 
2. Cut the gasket: Using a sharp utility knife, carefully cut the outer and inner perimeters of the gasket. A thumb can be used as a pivot for a cleaner cut. It's often easier to leave the outside intact and cut from the inside out to keep it stable. 
3. Create bolt holes: 
   • Align the gasket over a piece of scrap material. 
   • Place a nut below where the bolt hole should be and hammer the correct size bolt down into the hole to cut it out. 
   • You can also place the gasket and bolt, then use a nut and bolt to punch through. 
4. Assemble:
   • Ensure both sides of the gasket and the mating surfaces are clean and smooth. 
   • Apply a gasket sealant or dressing to improve the seal and prevent sticking later, especially with improvised materials. 
   • Install the gasket and reassemble the parts. 

Is valve cover gasket rubber?

The valve cover gasket is a thin strip of rubber or cork that creates a tight seal between the valve cover and the cylinder head. Because the gasket is delicate and prone to damage, continuous exposure to dirt, debris, and heat over time will cause it to become brittle and crack, losing its ability to prevent leaks.

What material are valve covers made of?

Valve covers are made from several materials, including aluminum, steel, plastic, and composite materials. Aluminum and steel are common in older vehicles for their durability, while plastic and composite covers are prevalent in modern cars due to their lower weight and cost-effectiveness.
 
Metal valve covers

• Aluminum: Offers a good balance of durability and light weight, and can help with engine cooling. 
• Steel: Very strong and can handle high pressure, though it is heavier than aluminum. 
• Magnesium: Used in some applications, but may not last as long as aluminum. 

Plastic and composite valve covers 

• Plastic/Composite: Found in many modern engines to reduce weight and manufacturing costs. They can be susceptible to cracking or warping over time due to heat exposure. Some plastic valve covers also have integrated features like a crankcase vent valve, which can be a point of failure.