Best Radiator Sealers. Reviews November, 2020

Prestone AS145 Radiator Sealer Stop Leak - 11 oz.

Search only Prestone brand name
Prestone AS145 Radiator Sealer Stop Leak - 11 oz.

Current price: 11.52 USD


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Height: 5.64 Inches

Length: 1.91 Inches

Width: 3.04 Inches

Weight: 0.82 Pounds

  • Stops the leak as well as the corrosive condition that causes it
  • Seals even large leaks without interfering with the flow through the radiator or heater core
  • Combination of natural and synthetic components provides the ability to seal leaks up to 0.020" x 0.5"
  • Boosts corrosion inhibitors to protect against pitting and corrosion, which cause radiator leaks
  • Patented formula quickly stops leaks in radiators, water pumps, and heater cores

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BlueDevil Radiator & Block Sealer

Search only BlueDevil Products brand name
BlueDevil Radiator & Block Sealer

Current price: 37.99 USD


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  • Stops the leak as well as the corrosive condition that causes it
  • Seals even large leaks without interfering with the flow through the radiator or heater core
  • Combination of natural and synthetic components provides the ability to seal leaks up to 0.020" x 0.5"
  • Boosts corrosion inhibitors to protect against pitting and corrosion, which cause radiator leaks
  • Patented formula quickly stops leaks in radiators, water pumps, and heater cores
  • Guaranteed
  • Safe and Easy to use.
  • Contains no solids or fibrous materials.
  • Works effectively on plastic, aluminum and/or metal radiators
  • Permanent repair for radiator and block leaks.

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BlueDevil 32oz Head Gasket Sealer w/Radiator Flush

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BlueDevil 32oz Head Gasket Sealer w/Radiator Flush

Current price: 64.95 USD


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  • Stops the leak as well as the corrosive condition that causes it
  • Seals even large leaks without interfering with the flow through the radiator or heater core
  • Combination of natural and synthetic components provides the ability to seal leaks up to 0.020" x 0.5"
  • Boosts corrosion inhibitors to protect against pitting and corrosion, which cause radiator leaks
  • Patented formula quickly stops leaks in radiators, water pumps, and heater cores
  • Guaranteed
  • Safe and Easy to use.
  • Contains no solids or fibrous materials.
  • Works effectively on plastic, aluminum and/or metal radiators
  • Permanent repair for radiator and block leaks.
  • Includes 32oz Head Gasket sealer and 32 oz Flush
  • Permanently Seals Leaking Heater Cores
  • Permanently Seals Warped & Cracked Heads
  • Permanently Seals Leaking Radiators
  • Permanently Seals Blown Head Gaskets

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Bar's Leaks HDC Radiator Stop Leak Tablet - 60 Grams

Search only Bar's Leaks brand name
Bar's Leaks HDC Radiator Stop Leak Tablet - 60 Grams

Current price: 2.25 USD


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Height: 0.8 Inches

Length: 7.5 Inches

Width: 5 Inches

Weight: 0.2 Pounds

Warranty: Manufacturer Warranty

  • Stops the leak as well as the corrosive condition that causes it
  • Seals even large leaks without interfering with the flow through the radiator or heater core
  • Combination of natural and synthetic components provides the ability to seal leaks up to 0.020" x 0.5"
  • Boosts corrosion inhibitors to protect against pitting and corrosion, which cause radiator leaks
  • Patented formula quickly stops leaks in radiators, water pumps, and heater cores
  • Guaranteed
  • Safe and Easy to use.
  • Contains no solids or fibrous materials.
  • Works effectively on plastic, aluminum and/or metal radiators
  • Permanent repair for radiator and block leaks.
  • Includes 32oz Head Gasket sealer and 32 oz Flush
  • Permanently Seals Leaking Heater Cores
  • Permanently Seals Warped & Cracked Heads
  • Permanently Seals Leaking Radiators
  • Permanently Seals Blown Head Gaskets
  • Helps control electrolysis
  • Lubricates water pump seals
  • Inhibits rust and corrosion
  • Conditions cooling system
  • Seals leaks

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Zecol Mendtite Heavy Duty Radiator Seal

Search only TISCO brand name
Zecol Mendtite Heavy Duty Radiator Seal

Current price: 18.99 USD


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  • Stops the leak as well as the corrosive condition that causes it
  • Seals even large leaks without interfering with the flow through the radiator or heater core
  • Combination of natural and synthetic components provides the ability to seal leaks up to 0.020" x 0.5"
  • Boosts corrosion inhibitors to protect against pitting and corrosion, which cause radiator leaks
  • Patented formula quickly stops leaks in radiators, water pumps, and heater cores
  • Guaranteed
  • Safe and Easy to use.
  • Contains no solids or fibrous materials.
  • Works effectively on plastic, aluminum and/or metal radiators
  • Permanent repair for radiator and block leaks.
  • Includes 32oz Head Gasket sealer and 32 oz Flush
  • Permanently Seals Leaking Heater Cores
  • Permanently Seals Warped & Cracked Heads
  • Permanently Seals Leaking Radiators
  • Permanently Seals Blown Head Gaskets
  • Helps control electrolysis
  • Lubricates water pump seals
  • Inhibits rust and corrosion
  • Conditions cooling system
  • Seals leaks
  • Warranty

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BlueDevil Head Gasket Sealer (38386)

Search only BlueDevil Products brand name
BlueDevil Head Gasket Sealer (38386)

Current price: 48.39 USD

Saving: $6.56 (12%)


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Weight: 2.87 Pounds

Warranty: LIMITED WARRANTY

  • Stops the leak as well as the corrosive condition that causes it
  • Seals even large leaks without interfering with the flow through the radiator or heater core
  • Combination of natural and synthetic components provides the ability to seal leaks up to 0.020" x 0.5"
  • Boosts corrosion inhibitors to protect against pitting and corrosion, which cause radiator leaks
  • Patented formula quickly stops leaks in radiators, water pumps, and heater cores
  • Guaranteed
  • Safe and Easy to use.
  • Contains no solids or fibrous materials.
  • Works effectively on plastic, aluminum and/or metal radiators
  • Permanent repair for radiator and block leaks.
  • Includes 32oz Head Gasket sealer and 32 oz Flush
  • Permanently Seals Leaking Heater Cores
  • Permanently Seals Warped & Cracked Heads
  • Permanently Seals Leaking Radiators
  • Permanently Seals Blown Head Gaskets
  • Helps control electrolysis
  • Lubricates water pump seals
  • Inhibits rust and corrosion
  • Conditions cooling system
  • Seals leaks
  • Warranty
  • Permanent Repair
  • Safe and easy to use
  • Alternative solution for costly and time consuming repairs 
  • Contains no solid or particulate matter that can harm a vehicles engine 

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BlueDevil Pour-N-Go Head Gasket Sealer

Search only BlueDevil Products brand name
BlueDevil Pour-N-Go Head Gasket Sealer

Current price: 31.25 USD


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Weight: 1 Pounds

  • Stops the leak as well as the corrosive condition that causes it
  • Seals even large leaks without interfering with the flow through the radiator or heater core
  • Combination of natural and synthetic components provides the ability to seal leaks up to 0.020" x 0.5"
  • Boosts corrosion inhibitors to protect against pitting and corrosion, which cause radiator leaks
  • Patented formula quickly stops leaks in radiators, water pumps, and heater cores
  • Guaranteed
  • Safe and Easy to use.
  • Contains no solids or fibrous materials.
  • Works effectively on plastic, aluminum and/or metal radiators
  • Permanent repair for radiator and block leaks.
  • Includes 32oz Head Gasket sealer and 32 oz Flush
  • Permanently Seals Leaking Heater Cores
  • Permanently Seals Warped & Cracked Heads
  • Permanently Seals Leaking Radiators
  • Permanently Seals Blown Head Gaskets
  • Helps control electrolysis
  • Lubricates water pump seals
  • Inhibits rust and corrosion
  • Conditions cooling system
  • Seals leaks
  • Warranty
  • Permanent Repair
  • Safe and easy to use
  • Alternative solution for costly and time consuming repairs 
  • Contains no solid or particulate matter that can harm a vehicles engine 
  • Permanently Seals Blown, Cracked or Leaking Head Gaskets
  • Used for 4 cylinder and v-6 engines
  • Easy to Use Pour-n-go
  • Do-It-Yourself Formula

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Bar's Leaks 1186 Liquid Aluminum Stop Leak - 16.9 oz

Search only Bar's Leaks brand name
Bar's Leaks 1186 Liquid Aluminum Stop Leak - 16.9 oz

Current price: 6.79 USD

Saving: $7.83 (54%)


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Height: 7.4 Inches

Length: 2.6 Inches

Width: 2.6 Inches

Weight: 1.2 Pounds

Warranty: 1 year manufacturer

  • Stops the leak as well as the corrosive condition that causes it
  • Seals even large leaks without interfering with the flow through the radiator or heater core
  • Combination of natural and synthetic components provides the ability to seal leaks up to 0.020" x 0.5"
  • Boosts corrosion inhibitors to protect against pitting and corrosion, which cause radiator leaks
  • Patented formula quickly stops leaks in radiators, water pumps, and heater cores
  • Guaranteed
  • Safe and Easy to use.
  • Contains no solids or fibrous materials.
  • Works effectively on plastic, aluminum and/or metal radiators
  • Permanent repair for radiator and block leaks.
  • Includes 32oz Head Gasket sealer and 32 oz Flush
  • Permanently Seals Leaking Heater Cores
  • Permanently Seals Warped & Cracked Heads
  • Permanently Seals Leaking Radiators
  • Permanently Seals Blown Head Gaskets
  • Helps control electrolysis
  • Lubricates water pump seals
  • Inhibits rust and corrosion
  • Conditions cooling system
  • Seals leaks
  • Warranty
  • Permanent Repair
  • Safe and easy to use
  • Alternative solution for costly and time consuming repairs 
  • Contains no solid or particulate matter that can harm a vehicles engine 
  • Permanently Seals Blown, Cracked or Leaking Head Gaskets
  • Used for 4 cylinder and v-6 engines
  • Easy to Use Pour-n-go
  • Do-It-Yourself Formula
  • Special Shipping Information: This item cannot be returned and has additional shipping restrictions
  • Repairs gasket leaks
  • Seals freeze plug leaks
  • Seals radiator leaks
  • Bar's Leaks Liquid Aluminum Stop Leak seals radiator leaks. Seals freeze plug leaks. Repairs gasket leaks and heater core leaks. Lowers water temperature.

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K-SEAL Coolant Leak Repair, ST5501 8oz, Multi-Purpose Formula Stops Leaks in the Radiator, Head Gasket, Block, Water Pump Casing, Heater Core, and Freeze Plug - Pour and Go - Trade Trusted-Stop Leak

Search only K-Seal brand name
K-SEAL Coolant Leak Repair, ST5501 8oz, Multi-Purpose Formula Stops Leaks in the Radiator, Head Gasket, Block, Water Pump Casing, Heater Core, and Freeze Plug - Pour and Go - Trade Trusted-Stop Leak

Current price: 12.47 USD

Saving: $2.52 (17%)


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Height: 5.99999999388 Inches

Length: 7.87401574 Inches

Width: 1.99999999796 Inches

Weight: 0.60406659788 Pounds

Warranty: When K-Seal makes a repair we guarantee it will be permanent

  • Stops the leak as well as the corrosive condition that causes it
  • Seals even large leaks without interfering with the flow through the radiator or heater core
  • Combination of natural and synthetic components provides the ability to seal leaks up to 0.020" x 0.5"
  • Boosts corrosion inhibitors to protect against pitting and corrosion, which cause radiator leaks
  • Patented formula quickly stops leaks in radiators, water pumps, and heater cores
  • Guaranteed
  • Safe and Easy to use.
  • Contains no solids or fibrous materials.
  • Works effectively on plastic, aluminum and/or metal radiators
  • Permanent repair for radiator and block leaks.
  • Includes 32oz Head Gasket sealer and 32 oz Flush
  • Permanently Seals Leaking Heater Cores
  • Permanently Seals Warped & Cracked Heads
  • Permanently Seals Leaking Radiators
  • Permanently Seals Blown Head Gaskets
  • Helps control electrolysis
  • Lubricates water pump seals
  • Inhibits rust and corrosion
  • Conditions cooling system
  • Seals leaks
  • Warranty
  • Permanent Repair
  • Safe and easy to use
  • Alternative solution for costly and time consuming repairs 
  • Contains no solid or particulate matter that can harm a vehicles engine 
  • Permanently Seals Blown, Cracked or Leaking Head Gaskets
  • Used for 4 cylinder and v-6 engines
  • Easy to Use Pour-n-go
  • Do-It-Yourself Formula
  • Special Shipping Information: This item cannot be returned and has additional shipping restrictions
  • Repairs gasket leaks
  • Seals freeze plug leaks
  • Seals radiator leaks
  • Bar's Leaks Liquid Aluminum Stop Leak seals radiator leaks. Seals freeze plug leaks. Repairs gasket leaks and heater core leaks. Lowers water temperature.
  • CUSTOMER SUPPORT: If K-Seal engine coolant leak stop doesn’t seal, 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 worldwide!
  • SCIENTIFICALLY TESTED: Safe and effective, our cracked block repair can seal 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.
  • POUR AND GO: Our cooling system sealer is easy to use: just shake the bottle, add to your radiator/overflow and run the engine! Unlike some traditional products, it mixes with all types of antifreeze, absolutely no draining or flushing required.
  • SEALS CRACKS AND STOPS LEAKS: A DIY alternative to costly repairs, our coolant leak fix permanently seals cracks and holes! It quickly repairs your leaking radiator, freeze plug, heater core and water pump casing with no adverse impact on efficiency.
  • REPAIRS IN MINUTES: Formulated to permanently weld radiators, including hard plastic aluminum heads and blocks in old and new cars. The only car radiator and gasket sealant university tested to meet ASTM D3147. Save time/money. US Bestseller

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J-B Weld DS-114 PERM-O-Seal Radiator Stop Leak - 0.7 oz.

Search only J-B Weld brand name
J-B Weld DS-114 PERM-O-Seal Radiator Stop Leak - 0.7 oz.

Current price: 7.1 USD


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Weight: 0.1 Pounds

Warranty: 1 year manufacturer

  • Stops the leak as well as the corrosive condition that causes it
  • Seals even large leaks without interfering with the flow through the radiator or heater core
  • Combination of natural and synthetic components provides the ability to seal leaks up to 0.020" x 0.5"
  • Boosts corrosion inhibitors to protect against pitting and corrosion, which cause radiator leaks
  • Patented formula quickly stops leaks in radiators, water pumps, and heater cores
  • Guaranteed
  • Safe and Easy to use.
  • Contains no solids or fibrous materials.
  • Works effectively on plastic, aluminum and/or metal radiators
  • Permanent repair for radiator and block leaks.
  • Includes 32oz Head Gasket sealer and 32 oz Flush
  • Permanently Seals Leaking Heater Cores
  • Permanently Seals Warped & Cracked Heads
  • Permanently Seals Leaking Radiators
  • Permanently Seals Blown Head Gaskets
  • Helps control electrolysis
  • Lubricates water pump seals
  • Inhibits rust and corrosion
  • Conditions cooling system
  • Seals leaks
  • Warranty
  • Permanent Repair
  • Safe and easy to use
  • Alternative solution for costly and time consuming repairs 
  • Contains no solid or particulate matter that can harm a vehicles engine 
  • Permanently Seals Blown, Cracked or Leaking Head Gaskets
  • Used for 4 cylinder and v-6 engines
  • Easy to Use Pour-n-go
  • Do-It-Yourself Formula
  • Special Shipping Information: This item cannot be returned and has additional shipping restrictions
  • Repairs gasket leaks
  • Seals freeze plug leaks
  • Seals radiator leaks
  • Bar's Leaks Liquid Aluminum Stop Leak seals radiator leaks. Seals freeze plug leaks. Repairs gasket leaks and heater core leaks. Lowers water temperature.
  • CUSTOMER SUPPORT: If K-Seal engine coolant leak stop doesn’t seal, 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 worldwide!
  • SCIENTIFICALLY TESTED: Safe and effective, our cracked block repair can seal 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.
  • POUR AND GO: Our cooling system sealer is easy to use: just shake the bottle, add to your radiator/overflow and run the engine! Unlike some traditional products, it mixes with all types of antifreeze, absolutely no draining or flushing required.
  • SEALS CRACKS AND STOPS LEAKS: A DIY alternative to costly repairs, our coolant leak fix permanently seals cracks and holes! It quickly repairs your leaking radiator, freeze plug, heater core and water pump casing with no adverse impact on efficiency.
  • REPAIRS IN MINUTES: Formulated to permanently weld radiators, including hard plastic aluminum heads and blocks in old and new cars. The only car radiator and gasket sealant university tested to meet ASTM D3147. Save time/money. US Bestseller
  • DO IT YOURSELF: Big or small, you can DIY it with J-B. Our heavy duty adhesives repair & restore it right the first time. JB Weld delivers the legendary performance of the World's Strongest Bond.
  • DURABLE FAST FIX: The special compound will quickly seal leaks and will also act as a rust inhibitor and lubricant to internal cooling system parts. It will not clog or harm your cooling system.
  • MONEY SAVING REPAIR SOLUTION: The powered concentrate allows for an economical repair as compared to liquid based alternatives that use similar technology.
  • WHAT THE PROS USE: Mechanics, repair pros, and any avid DIYer knows our products bond strong to a variety of surfaces in even the toughest environments; and they have always been made in the USA.
  • JB WELD PERM O SEAL : Is a specially formulated non-toxic compound ground to a very fine particle size to quickly mix and flow into all areas of the cooling system to find and seal leaks.

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