Reviews

LAST UPDATED: March 23, 2020

Best Automotive Seam Sealer: Keep Your Vehicle Free of Rust and Drafts

Protect your vehicle from rust and corrosion with these automotive seam sealers

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The Review Team

  • Product Network

    17 Products

  • Clock

    10 Hours

  • Reviews

    14 Reviews

How We Decided

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PUBLISHED ON March 23, 2020

If you’ve noticed your car is beginning to develop rust, is in need of a body repair, or perhaps you feel a draft while driving, don’t contact your local garage just yet. There’s a quick and effective way to resolve this at home, without spending a lot of money.

Automotive body seam sealers are an inexpensive solution to these issues, and they come in a variety of options. For two figures, you can completely restore your vehicle and improve its longevity. Check out the best automotive seam sealers to protect your vehicle.

  • Best Overall
    Eastwood Brushable Seam Sealer
    Summary
    Summary
    This brushable product has excellent adhesion to prevent air and rain from entering your vehicle. Its flexible design means it won’t shrink surfaces, or harden or crack once it’s dried.
    Pros
    Pros
    You can paint over the undercoating in 60 minutes. Waterproof and insulating features.
    Cons
    Cons
    You need to purchase the brush separately. No nozzle for an easy application.
  • Best Overall
    Eastwood Brushable Seam Sealer
  • Best Value
    3M Dynatron Auto Seam Sealer
    Summary
    Summary
    3M Dynatron designed this sealer for a range of materials, including bare metal or painted surfaces. It blocks moisture to prevent corrosion and mold from forming.
    Pros
    Pros
    Thick consistency to reduce drips when applying the product. Fast skinning begins after 10-15 minutes.
    Cons
    Cons
    Not suitable for use in high temperatures. Doesn’t come with instructions, making it frustrating for novices.
  • Best Value
    3M Dynatron Auto Seam Sealer
  • Honorable Mention
    ACDelco Auto Body Joint and Seam Filler
    Summary
    Summary
    ACDelco is a non-sagging product that won’t crack or shrink after it’s applied. This water-resistant product is flexible and non-staining.
    Pros
    Pros
    Provides excellent adhesive to a range of surfaces. An effective solution to leaks and cracks.
    Cons
    Cons
    Avoid contact with  exhausts and catalytic converters. Tends to dry softer than competitive products.
  • Honorable Mention
    ACDelco Auto Body Joint and Seam Filler

    If you’ve noticed your car is beginning to develop rust, is in need of a body repair, or perhaps you feel a draft while driving, don’t contact your local garage just yet. There’s a quick and effective way to resolve this at home, without spending a lot of money.

    Automotive body seam sealers are an inexpensive solution to these issues, and they come in a variety of options. For two figures, you can completely restore your vehicle and improve its longevity. Check out the best automotive seam sealers to protect your vehicle.

    Best Automotive Seam Sealer Reviews & Recommendations 2020

    Best Overall

    This brushable product is ideal for adding anti-corrosion protection to your auto’s body if you want to target a large surface area. In less than 60 minutes, it’s completely dry, allowing you to paint on top to cover its gray finish.


    Thanks to its waterproof and insulating features, this makes a great option for preventing cold air and rain from entering your vehicle. Plus, it prevents rust and corrosion from forming on your car in the first place.


    Due to this type of product, you’ll need to purchase a brush separately, as it doesn’t come with tools. Plus, it dries a gray color, so you’ll need to paint over the result to match your auto’s body.

    Best Value

    The 3M Dynatron heavy-duty product is permanently elastic and non-staining, making it ideal if you don’t plan to paint over the surfaces afterward. Apply it to gaps and voids in your vehicle—including the interior and exterior. It’ll reduce the chances of mildew and mold growth.


    Its thick consistency makes this a great product to apply as it doesn’t produce any drips. Not all sealers are thick, which can make the application complex. It’s also reasonably priced. 


    However, you should consider that the 3M Dynatron product doesn’t come with instructions or a long nozzle, which isn’t ideal for beginners or targeting hard-to-reach areas.

    Honorable Mention

    This ACDelco seam filler provides an excellent solution for sealing cracks, while providing a non-staining result that won’t crack. You can also paint over the finished surface just 60 minutes after you’ve applied the product.


    It’s quick-drying and has a thick consistency, helping you to apply the solution without it pouring everywhere. Plus, it’s trust-worthy enough to use on panels that have been involved in a collision.


    However, avoid using this seam filler near high-temperature objects, as it’s unsafe. Some customer reviews also report that it doesn’t dry as hard as competitor products.

    Why Trust Us


    All of our reviews are based on market research, expert input, and practical experience with most products we include. This way, we offer genuine, accurate guides to help you find the best picks.

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    Benefits of Automotive Seam Sealers

    • Prolong the vehicle’s life. Using a high-quality seam sealer will prolong your vehicle’s lifespan after restoration. This is because most rust problems start in the seams.
    • Waterproof your car. If you’ve noticed drips of water entering your vehicle when it’s raining, these products will fill in any gaps, so no harsh winds or water can enter. Seam sealers are also resistant to motor oil.
    • Improve a paint job. Using a seam sealer before applying a new coat of paint can be essential to ensure all panels and joints are connected properly for a smooth, even finish.

    Types of Automotive Seam Sealers

    Sealants

    Sealants come in a nozzle, so you can specifically apply the product to narrow areas, making them great for a touch-up job. Most sealants are transparent when they dry, so there’s no need to paint over the surface. This makes them a popular option for a quick-fix or sealing small cracks that are allowing air and water to enter.

    Brushable

    A brushable seam sealer presents itself in a tin, which you apply to the surface using a paintbrush. This is an ideal option if you wish to target a large surface area without the hassle of applying a narrow tube across the entire area. As brushable sealers are designed for large areas—which is great as a body filler—they make a smooth, quick-drying base, making the surface paintable.

    Top Brands

    Eastwood

    Founded in 1978 and headquartered in Pennsylvania, Eastwood provides easy-to-use automotive tools and accessories so you can perform DIY car care from home. They also specialize in a range of seam sealers, including kits for an easy application. We recommend the Eastwood Insulated Seam Sealer, which is waterproof and offers insulating properties.

    Speedokote

    Founded in 1960 and nestled in California, Speedokote is a reputable automotive brand that sells auto parts, thinners, primers, paint, masking, sandpaper, and of course, sealers. Their high-quality, budget-friendly products are effective and easy to use for novices. We recommend the Black Fast Setting Sealer, which takes around one hour to dry completely.

    Evercoat

    This company was founded in 1953 and is headquartered in the United States, as well as offices around the world. They specialize in designing and manufacturing automotive products after collisions. One of its top products, the Maxim Control Seam Seal features a user-friendly nozzle for controlled applications. 

    Automotive Seam Sealer Pricing

    • Up to $20: The cheapest seam sealers will offer a waterproof feature and won’t crack once they’ve dried.
    • $20 and up: For the top-quality seam sealers, you can expect a quick-drying action, plus insulating features to prevent the inside of your car from getting cold. These will also likely come with different sized nozzles for a convenient application.

    Key Features

    Water- and Corrosion-Proof

    One of the biggest features of this type of product is that they’re water- and corrosion-proof. This creates a protective layer on your vehicle—whether that’s on the interior or exterior—to prevent weather from eroding your car. 

    Compatible With a Range of Materials

    Thanks to the versatility that seam sealers offer, most are compatible with numerous materials,  including metal, chrome, and plastic. This feature allows you to use the product on a range of surfaces in your vehicle, from under the hood to plastic components on the dashboard.

    No Shrinkage

    As sealers are designed for a range of surfaces and components in your vehicle, one of their key features is not shrinking the materials. Otherwise, the surfaces would pull apart once the sealer has dried. Plus, the sealer won’t crack once the application is complete.

    Other Considerations

    • High Temperature Rating. If you plan to use the seam sealer around the engine, you’ll require a product that has a high temperature rating. Ensure it can operate on surfaces up to 450 degrees Fahrenheit.
    • Long-Reach Applicator. The applicator’s design can make a huge difference in terms of convenience and ease. Opt for a sealer with a long-reach design that allows you to target deep into the hood without putting your arm far in.
    • Transparency. This isn’t essential for everyone, as it depends on whether you wish to paint the surface once the sealer has dried. Check the product descriptions to learn what the finish looks like.

    Best Automotive Seam Sealer Reviews & Recommendations 2020

    Best Overall

    This brushable product is ideal for adding anti-corrosion protection to your auto’s body if you want to target a large surface area. In less than 60 minutes, it’s completely dry, allowing you to paint on top to cover its gray finish.


    Thanks to its waterproof and insulating features, this makes a great option for preventing cold air and rain from entering your vehicle. Plus, it prevents rust and corrosion from forming on your car in the first place.


    Due to this type of product, you’ll need to purchase a brush separately, as it doesn’t come with tools. Plus, it dries a gray color, so you’ll need to paint over the result to match your auto’s body.

    Eastwood Brushable Seam Sealer}
    Amazon

    This brushable product is ideal for adding anti-corrosion protection to your auto’s body if you want to target a large surface area. In less than 60 minutes, it’s completely dry, allowing you to paint on top to cover its gray finish.


    Thanks to its waterproof and insulating features, this makes a great option for preventing cold air and rain from entering your vehicle. Plus, it prevents rust and corrosion from forming on your car in the first place.


    Due to this type of product, you’ll need to purchase a brush separately, as it doesn’t come with tools. Plus, it dries a gray color, so you’ll need to paint over the result to match your auto’s body.

    Click Here to See Prices on Amazon

    Best Value

    The 3M Dynatron heavy-duty product is permanently elastic and non-staining, making it ideal if you don’t plan to paint over the surfaces afterward. Apply it to gaps and voids in your vehicle—including the interior and exterior. It’ll reduce the chances of mildew and mold growth.


    Its thick consistency makes this a great product to apply as it doesn’t produce any drips. Not all sealers are thick, which can make the application complex. It’s also reasonably priced. 


    However, you should consider that the 3M Dynatron product doesn’t come with instructions or a long nozzle, which isn’t ideal for beginners or targeting hard-to-reach areas.

    3M Dynatron Auto Seam Sealer}
    Amazon

    The 3M Dynatron heavy-duty product is permanently elastic and non-staining, making it ideal if you don’t plan to paint over the surfaces afterward. Apply it to gaps and voids in your vehicle—including the interior and exterior. It’ll reduce the chances of mildew and mold growth.


    Its thick consistency makes this a great product to apply as it doesn’t produce any drips. Not all sealers are thick, which can make the application complex. It’s also reasonably priced. 


    However, you should consider that the 3M Dynatron product doesn’t come with instructions or a long nozzle, which isn’t ideal for beginners or targeting hard-to-reach areas.

    Click Here to See Prices on Amazon

    Honorable Mention

    This ACDelco seam filler provides an excellent solution for sealing cracks, while providing a non-staining result that won’t crack. You can also paint over the finished surface just 60 minutes after you’ve applied the product.


    It’s quick-drying and has a thick consistency, helping you to apply the solution without it pouring everywhere. Plus, it’s trust-worthy enough to use on panels that have been involved in a collision.


    However, avoid using this seam filler near high-temperature objects, as it’s unsafe. Some customer reviews also report that it doesn’t dry as hard as competitor products.

    ACDelco Joint and Seam Filler}
    Amazon

    This ACDelco seam filler provides an excellent solution for sealing cracks, while providing a non-staining result that won’t crack. You can also paint over the finished surface just 60 minutes after you’ve applied the product.


    It’s quick-drying and has a thick consistency, helping you to apply the solution without it pouring everywhere. Plus, it’s trust-worthy enough to use on panels that have been involved in a collision.


    However, avoid using this seam filler near high-temperature objects, as it’s unsafe. Some customer reviews also report that it doesn’t dry as hard as competitor products.

    Click Here to See Prices on Amazon

    Tips

    • The surface you apply the sealer must be clean, dry, and free from grease.
    • Most products don’t allow you to paint over them immediately, so check the instructions. You may have to wait for the sealer to dry overnight. 
    • Always follow safety instructions when applying the sealer. Most require you to wear protective gear so you don’t inhale fumes.

    FAQs

    Q: How often should you replace your car’s sealant?

    A: We recommend monitoring your vehicle’s rust patches. If you notice them forming, be proactive and purchase a seam sealer. Alternatively, replacements every five years or so should keep this issue from arising.

    Q: Can you use a silicone sealant on your vehicle?

    A: No. You can’t paint over silicone, which will leave your vehicle looking unpresentable. More importantly, it takes a lot of preparation before applying the product and doesn’t provide a long-lasting effect. 

    Q: Are all seam sealers the same?

    A: Most seam sealers have similar qualities, though they’re not all the same. Some leave a smoother surface, while others need more preparation before painting on them. 

    Final Thoughts

    Our top recommendation is the Eastwood Brushable Seam Sealer. This reputable brand has experience in creating products to prevent rust from forming.

    Alternatively, for a budget-friendly option, choose the 3M Dynatron Auto Seam Sealer. It’s compatible with a range of surfaces and easy to work with.