10 Best Head Gasket Sealers 2025 in the United States

The Permatex 82180 Ultra Black Maximum Oil Resistance RTV Silicone Gasket Maker is a solid choice for anyone looking to create or replace gaskets in various automotive applications. Its non-corrosive formula is sensor-safe and offers superior adhesion, making it particularly effective on oily surfaces. This feature is a big plus, especially for users working on tasks involving engine oil or transmission fluid, as it ensures a durable and long-lasting seal. The gasket maker operates effectively within a broad temperature range of -65°F to 500°F, which enhances its versatility in different automotive environments.

With a full cure time of 24 hours, it’s essential to plan your repairs accordingly since you'll need to allow adequate time for the product to set properly. For ease of application, the silicone is user-friendly, allowing both DIY enthusiasts and professional mechanics to work with it without too much hassle.

While it boasts high flexibility and resistance to aging, the 24-hour curing time may be lengthy for those in a hurry to finish repairs. Additionally, the product comes in a small volume (3.35 fluid ounces), which might not be sufficient for larger jobs, necessitating the purchase of multiple tubes for extensive applications.

The K-Seal ST5516 Heavy-Duty Multi-Purpose Coolant Leak Repair offers a convenient solution for those needing to quickly address leaks in their vehicle's cooling system. It stands out for its compatibility with all types of antifreeze and ease of application, requiring no draining or flushing—just shake, pour, and go.

This product is particularly designed for heavy-duty and industrial use, making it suitable for commercial and agricultural vehicles. Its professional-grade reliability is backed by positive customer reviews and independent testing, providing a durable and long-lasting repair without clogging the cooling system.

However, while it's marketed as a permanent solution, the product may not work for all types of leaks or severely damaged components, and some users might find the results vary based on the condition of their engine. Additionally, it's worth noting that although it works quickly, the product's effectiveness largely depends on following the application instructions precisely. For those with minor to moderate coolant leaks, the K-Seal ST5516 offers a quick and practical fix, but for more severe issues, further mechanical intervention might be necessary.

The Permatex 80697 Copper Spray-A-Gasket Hi-Temp Adhesive Sealant is a reliable choice for those needing a high-temperature adhesive solution. Its compatibility with cylinder head gaskets, exhaust manifold gaskets, and other high-temperature applications is a significant advantage. The product performs well in extreme temperatures, with a tolerance range of -50°F to 500°F (-45°C to 260°C), making it suitable for various automotive repairs.

The fast-drying formula is convenient, allowing for quicker completion of tasks. Additionally, its ability to fill minor surface imperfections enhances its sealing effectiveness and prevents gasket burnout by dissipating heat effectively. The copper material further aids in heat transfer and durability. Application is straightforward due to its spray form, which ensures even coverage and ease of use.

Weighing 12 ounces and with compact dimensions, it is easy to store and handle. Despite minor drawbacks, such as potentially needing trial for curing time, the Permatex 80697 remains a versatile and effective option for high-temperature sealing needs.