10 Best Head Gasket Sealer of December 2025

• Repairs blown head and intake gasket leaks
• Seals cracked cylinder heads and blocks
• Stops heater core and radiator leaks
• Fixes leaking freeze and core plugs

Bar's Leaks

• Fast-drying, metallic copper spray adhesive/sealant helps to dissipate heat, prevents gasket burnout, and improves heat transfer
• Fills minor surface irregularities, fills hot spots and surface imperfections
• Resists all types of automotive fluids, especially gasoline
• Temperature Range: -50°F to 500°F (-45°C to 260°C)
• Suggested Applications: Cylinder head gaskets, exhaust manifold gaskets, and other high temperature applications

Permatex

• Auto & Truck Maintenance
• Country of manufacture: United States
• Manufacturer: K&W

K&W

• Permanently seals a crack in the head gasket
• Do-It-Yourself Pour in Head Gasket Fix
• Used by thousands of repair shops nationwide
• Backed with a 100% Money-Back Guarantee
• Used for 8 Cylinder Engines

STEEL SEAL

• Do-It-Yourself Formula
• Easy to Use Pour-n-go
• Used for 4 cylinder and v-6 engines
• Permanently Seals Blown, Cracked or Leaking Head Gaskets

BlueDevil Products

• REPAIRS IN MINUTES: Permanently fix blown head gaskets, cracked heads and cracked/porous blocks including aluminum heads in old and new cars. The only head gasket and block sealant that is 3rd party tested to meet ASTM D3147. Save time/money
• SEALS CRACKS AND STOPS LEAKS: A DIY alternative to costly repairs, our head gasket fix permanently seals cracks and holes! Quickly repair your blocks, leaking radiator, freeze plug, heater core and water pump casing with no adverse impact on efficiency.
• POUR AND GO: Our head gasket sealer is easy to use just shake, add to your radiator/overflow and run the engine! Unlike some competitive products, it mixes with all types of antifreeze, absolutely no draining, flushing or pulling the thermostat required.
• SCIENTIFICALLY TESTED: Safe, effective, our head gasket and block repair seals leaks up to 1/32 of an inch! Once cured, the repair withstands the high pressure of the combustion chamber, all without failing or clogging the cooling system. US Bestseller
• CUSTOMER SUPPORT: If our head gasket repair leak doesn’t seal your intake gasket, the system might be over-pressurized. Check the Technical Specification section of this page for extra instructions for a successful repair. Over 8 million bottles sold.

K-Seal

• Easy Pour and Go Formula!
• Permanently fixes head gaskets, engine blocks, cooling systems, and cylinder heads.
• "Contains 3 unique technologies.Military-Strength Fibers create multi-layer repair over cracks with a web-like weave.Nanotechnology permanently fixes the smallest cracks and crevices.Cool-X Conditioner – lowers operating temperature as it circulates through cooling system."
• Seals larger holes with less fluid loss than competitive products as proven by lab test (ASTM D6107)
• Works with all antifreeze or plain water.

K&W

• Stops block leaks
• Seals cracked cylinder heads and blocks
• Repairs blown head gaskets
• Contains a combination of antifreeze compatible sodium silicate sealing liquid and various size gasket sealing particles which penetrate gaps & cracks and harden to permanently stop leaks.

Bar's Leaks

• Contains no solid or particulate matter that can harm a vehicles engine 
• Alternative solution for costly and time consuming repairs 
• Safe and easy to use
• Permanent Repair

BlueDevil Products

• Permanently seals a crack in the head gasket
• Do-It-Yourself Pour in Head Gasket Fix
• Used by thousands of repair shops nationwide
• Backed with a 100% Money-Back Guarantee
• Used for 6 Cylinder Engines

STEEL SEAL