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20 Best Heater Core Leak Sealant (2023 Updated)

Heater core leak sealant is a product that is used to seal leaks in the heater core. The product is applied to the outside of the heater core and then the leak is sealed. The product is available in a variety of sizes and is easy to apply.

20 Best Heater Core Leak Sealant

Product Image Product Name Features Price

Bar's Leaks – 11 oz. Radiator Stop Leak

  • Works with any color antifreeze
  • Stops leaks and drips from wear and age
  • Harmless to rubber, aluminum & other metals

K Seal Heavy Duty Permanent Coolant Leak Sealer – 16 oz jug

  • Item Weight 544 g
  • Product Dimensions 15 x 10.4 x 4.8 cm
  • Item Weight 544 gm

Bar's Leaks Liquid Aluminum Radiator Stop Leak 16.9oz

  • Safely Seals Leaks
  • Stops Overheating
  • Reduces Water Temperature

Bar's Leaks Pelletized Radiator Stop Leak 11oz

  • Seals leaks
  • Conditions cooling system
  • Inhibits rust and corrosion

Bar's Leaks – 18oz. Block Seal Liquid Copper Intake & Radiator Stop

  • One Step, No Draining Required
  • Antifreeze Compatible Sodium Silicate Formula
  • Permanent Cooling System Repair

K-Seal Permanent Leak Repair for Radiators, Head Gaskets, Blocks

  • Mixes with all antifreeze
  • No draining or flushing
  • Fixes cracks and leaks in radiator, head gasket, freeze plugs, cylinder heads, heater core, water pump casing and engine blocks

Liqui Moly 20132 – Radiator Stop Leak

  • LIQUI MOLY Radiator Stop-Leak completely seals such leaks immediately with ease.
  • Secures the combustion chamber from damages caused by coolant admission.

Rutland Black High Heat Silicone Sealant

  • Forms a flexible heat-resistant seal
  • Does not require heat to cure
  • Cures at room temperature

K-Seal Coolant Leak Repair, Head Gasket Sealant, Block Sealer, Radiator, Heater Core Stop Leak, ST5501

  • Advanced ceramic forumla Product Features: Anyone can use this product.
  • No Flushing or Draining.
  • You can even pour into the overflow tank. Mixes w/all types of antifreeze Just shake, pour & go.

K-Seal ST5501 Permanent Coolant Leak Repair – 8 oz bottle

  • No Flushing. Just shake, pour and go!
  • Mixes with all types of Antifreeze.
  • Multi Purpose ONe Step & Permanent.

Bar's Leaks Liquid Radiator Stop Leak – 10 oz

  • Seals leaks
  • Inhibits rust and corrosion helps control electrolysis
  • Conditions cooling system

AlumaSeal ASBPI12 Radiator Stop Leak Powder Blister Card – 20 G

  • Inhibits rust
  • Lubricates water pump
  • Quick permanent seal

Bar's Leaks Cooling System Repair – 16.9 fl oz bottle

  • Scientifically Formulated To Stop Coolant Leaks, Thereby Reducing Antifreeze Loss
  • Cooling System Repair Stops Overheating And Reduces Water Temperature

Liqui Moly Radiator Stop Leak 250ml

  • suitable for aluminum radiators.
  • permanently and reliably seals hairline cracks and small leaks.
  • no negative side effects on the water pump or heating circuit.

Wynns WY55864 Radiator Stop Leak 325ml

  • Stops and prevents leaks in the radiator and cooling
  • Stops and prevents leaks
  • Stops head gasket leaks

Rislone Cooling System Radiator Stop Leak

  • Product Type: Auto Oil
  • Model Number: 41186
  • Package Weight: 450.0 g
Bar's Leaks – 11 oz. Radiator Stop Leak
  • Works with any color antifreeze
  • Stops leaks and drips from wear and age
  • Harmless to rubber, aluminum & other metals
K Seal Heavy Duty Permanent Coolant Leak Sealer – 16 oz jug
  • Item Weight 544 g
  • Product Dimensions 15 x 10.4 x 4.8 cm
  • Item Weight 544 gm
Bar's Leaks Liquid Aluminum Radiator Stop Leak 16.9oz
  • Safely Seals Leaks
  • Stops Overheating
  • Reduces Water Temperature
Bar's Leaks Pelletized Radiator Stop Leak 11oz
  • Seals leaks
  • Conditions cooling system
  • Inhibits rust and corrosion
Bar's Leaks – 18oz. Block Seal Liquid Copper Intake & Radiator Stop
  • One Step, No Draining Required
  • Antifreeze Compatible Sodium Silicate Formula
  • Permanent Cooling System Repair
K-Seal Permanent Leak Repair for Radiators, Head Gaskets, Blocks
  • Mixes with all antifreeze
  • No draining or flushing
  • Fixes cracks and leaks in radiator, head gasket, freeze plugs, cylinder heads, heater core, water pump casing and engine blocks
Liqui Moly 20132 – Radiator Stop Leak
  • LIQUI MOLY Radiator Stop-Leak completely seals such leaks immediately with ease.
  • Secures the combustion chamber from damages caused by coolant admission.
Rutland Black High Heat Silicone Sealant
  • Forms a flexible heat-resistant seal
  • Does not require heat to cure
  • Cures at room temperature
K-Seal Coolant Leak Repair, Head Gasket Sealant, Block Sealer, Radiator, Heater Core Stop Leak, ST5501
  • Advanced ceramic forumla Product Features: Anyone can use this product.
  • No Flushing or Draining.
  • You can even pour into the overflow tank. Mixes w/all types of antifreeze Just shake, pour & go.
K-Seal ST5501 Permanent Coolant Leak Repair – 8 oz bottle
  • No Flushing. Just shake, pour and go!
  • Mixes with all types of Antifreeze.
  • Multi Purpose ONe Step & Permanent.
Bar's Leaks Liquid Radiator Stop Leak – 10 oz
  • Seals leaks
  • Inhibits rust and corrosion helps control electrolysis
  • Conditions cooling system
AlumaSeal ASBPI12 Radiator Stop Leak Powder Blister Card – 20 G
  • Inhibits rust
  • Lubricates water pump
  • Quick permanent seal
Bar's Leaks Cooling System Repair – 16.9 fl oz bottle
  • Scientifically Formulated To Stop Coolant Leaks, Thereby Reducing Antifreeze Loss
  • Cooling System Repair Stops Overheating And Reduces Water Temperature
Liqui Moly Radiator Stop Leak 250ml
  • suitable for aluminum radiators.
  • permanently and reliably seals hairline cracks and small leaks.
  • no negative side effects on the water pump or heating circuit.
Wynns WY55864 Radiator Stop Leak 325ml
  • Stops and prevents leaks in the radiator and cooling
  • Stops and prevents leaks
  • Stops head gasket leaks
Rislone Cooling System Radiator Stop Leak
  • Product Type: Auto Oil
  • Model Number: 41186
  • Package Weight: 450.0 g

1. Bar’s Leaks – 11 oz. Radiator Stop Leak

Bar's Leaks - 11 oz. Radiator Stop Leak

  • Works with any color antifreeze
  • Stops leaks and drips from wear and age
  • Harmless to rubber, aluminum & other metals

Check Latest Price

Sold By Price
Amazon.com – Seller
Walmart
AutoZone
Ace Hardware

Product Details

Specifications

Details
Product Type Stop Leak Concentrate
Container Size 11 oz
Brand Name Bar’s Leaks

Reviews From Real Customers

Brenda

2. K Seal Heavy Duty Permanent Coolant Leak Sealer – 16 oz jug

K Seal Heavy Duty Permanent Coolant Leak Sealer - 16 oz jug

  • Item Weight 544 g
  • Product Dimensions 15 x 10.4 x 4.8 cm
  • Item Weight 544 gm

Check Latest Price

Sold By Price
Amazon.com
eBay
Walmart
JBTools.com

Product Details

Specifications

Details
Product Dimensions 5.9 x 4.1 x 1.9 inches
Country of Origin USA
Is Discontinued By Manufacturer No

Reviews From Real Customers

S.
s.

3. Bar’s Leaks Liquid Aluminum Radiator Stop Leak 16.9oz

Bar's Leaks Liquid Aluminum Radiator Stop Leak 16.9oz

  • Safely Seals Leaks
  • Stops Overheating
  • Reduces Water Temperature

Check Latest Price

Sold By Price
Amazon.com
Walmart
AutoZone
Ace Hardware

Product Details

Specifications

Details
Excluded Ship States No
Item has MSDS (SDS)? Y
Special Instructions Use 1/2 (half) bottle in a small cooling system, such as 4 cylinders with no A/C. Use 1 (one) bottle for regular size systems, most 4, 6, 8 and 10 cylinder engines.
Item is Shipped at this Packaging Level N
Information Effective Date 2011-06-27 12:00:00

4. Bar’s Leaks Pelletized Radiator Stop Leak 11oz

Bar's Leaks Pelletized Radiator Stop Leak 11oz

  • Seals leaks
  • Conditions cooling system
  • Inhibits rust and corrosion
  • Lubricates water pump seals
  • Helps control electrolysis

Check Latest Price

Sold By Price
Amazon.com
eBay
Walmart
AutoZone

Product Details

Specifications

Details
Item has MSDS (SDS)? Y
Special Instructions Use 1 bottle for 6, 8 and 10 cylinder gas or diesel engines. For 4 cylinder engines, use 1/2 of liquid and pellets. One bottle treats systems up to 4 gallons.
Package Weight 11
Package Weight UOM OZ
Package Size 11 oz

Reviews From Real Customers

A.
JoeCLEAN

5. Bar’s Leaks – 18oz. Block Seal Liquid Copper Intake & Radiator Stop

Bar's Leaks - 18oz. Block Seal Liquid Copper Intake & Radiator Stop

  • One Step, No Draining Required
  • Antifreeze Compatible Sodium Silicate Formula
  • Permanent Cooling System Repair
  • Works With All Types Of Antifreeze Or Water

Check Latest Price

Sold By Price
Amazon.com
eBay
Walmart
AutoZone

Product Details

Specifications

Details
Item has MSDS (SDS)? Y
Special Instructions Use 1/2 (half) bottle in a small cooling systems, such as 4 cylinders with no A/C. Use 1 (one) bottle for regular size systems, which are most 4, 6, 8 and 10 cylinder engines. For larger systems, use 1 bottle for every 6 gallons of cooling system capacity.
Package Weight 18
Package Weight UOM OZ
Package Size 18 oz

Reviews From Real Customers

Jonas
Sigmaster

6. K-Seal Permanent Leak Repair for Radiators, Head Gaskets, Blocks

K-Seal Permanent Leak Repair for Radiators, Head Gaskets, Blocks

  • Mixes with all antifreeze
  • No draining or flushing
  • Fixes cracks and leaks in radiator, head gasket, freeze plugs, cylinder heads, heater core, water pump casing and engine blocks
  • Just shake, pour and go

Check Latest Price

Sold By Price
Amazon.com

Product Details

Specifications

Details
Product Dimensions 7.87 x 2 x 6 inches
Country of Origin USA
Is Discontinued By Manufacturer No

Reviews From Real Customers

Chato
Timo
Pat

7. Liqui Moly 20132 – Radiator Stop Leak

Liqui Moly 20132 - Radiator Stop Leak

  • LIQUI MOLY Radiator Stop-Leak completely seals such leaks immediately with ease.
  • Secures the combustion chamber from damages caused by coolant admission.
  • For all cooling water and heating systems with and without water filters.

Check Latest Price

Sold By Price
Amazon.com – Seller
ECS Tuning
FCP Euro
Turner Motorsport

Product Details

Specifications

Details
Length 6.5 in
Height 2.5 in
Width 2.5 in
Weight 0.7 lb

Reviews From Real Customers

2trippers
malco-birc

8. Rutland Black High Heat Silicone Sealant

Rutland Black High Heat Silicone Sealant

  • Forms a flexible heat-resistant seal
  • Does not require heat to cure
  • Cures at room temperature
  • For interior or exterior use
  • Remains flexible in high temperatures

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Sold By Price
Amazon.com – Seller
eBay
Walmart
Home Depot

Product Details

Specifications

Details
Weight 0.4 lb

Reviews From Real Customers

Cincinnatus
woundedknee99
Mitchell M.

9. K-Seal Coolant Leak Repair, Head Gasket Sealant, Block Sealer, Radiator, Heater Core Stop Leak, ST5501

K-Seal Coolant Leak Repair, Head Gasket Sealant, Block Sealer, Radiator, Heater Core Stop Leak, ST5501

  • Advanced ceramic forumla Product Features: Anyone can use this product.
  • No Flushing or Draining.
  • You can even pour into the overflow tank. Mixes w/all types of antifreeze Just shake, pour & go.
  • Works in just minutes Works on Head Gaskets, Radiator, Heater Cores, Freeze Plugs, Water Pump Casings, Cylinder Heads & Cracked Blocks.

Check Latest Price

Sold By Price
Amazon
eBay
Walmart
NAPA Auto Parts

Product Details

10. K-Seal ST5501 Permanent Coolant Leak Repair – 8 oz bottle

K-Seal ST5501 Permanent Coolant Leak Repair - 8 oz bottle

  • No Flushing. Just shake, pour and go!
  • Mixes with all types of Antifreeze.
  • Multi Purpose ONe Step & Permanent.

Check Latest Price

Sold By Price
Amazon
eBay
Agri Supply
ToolTopia.com

Product Details

Specifications

Details
Units in Package 1
Unit Size 8 oz

11. Bar’s Leaks Liquid Radiator Stop Leak – 10 oz

Bar's Leaks Liquid Radiator Stop Leak - 10 oz

  • Seals leaks
  • Inhibits rust and corrosion helps control electrolysis
  • Conditions cooling system
  • Lubricates water pump seal

Check Latest Price

Sold By Price
Amazon
eBay – 040817a
DK Hardware
SHC Supply

Product Details

Specifications

Details
Assembled Depth (in) 1.7 in
Assembled Height (In) 6.3 in
Assembled Width (in) 3.5 in
Assembled Weight (lbs) 1 lbs
Excluded Ship States No

Reviews From Real Customers

Nikki

12. Bar’s Leaks 1196 Grey Radiator Stop Leak – 11 oz.

Bar's Leaks 1196 Grey Radiator Stop Leak - 11 oz.

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Sold By Price
Amazon
Walmart – Shop Eddies

Product Details

Specifications

Details
Assembled Product Weight 10 lbs

13. 2pc Bar’s Leaks Stop Leak Concentrate 6 oz

2pc Bar's Leaks Stop Leak Concentrate 6 oz

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Amazon
Walmart – ADVENTURERS BAG

Product Details

14. 2pc Bar’s Leaks Stop Leak Concentrate 11 oz

2pc Bar's Leaks Stop Leak Concentrate 11 oz

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Amazon
Walmart – ADVENTURERS BAG

Product Details

15. AlumaSeal ASBPI12 Radiator Stop Leak Powder Blister Card – 20 G

AlumaSeal ASBPI12 Radiator Stop Leak Powder Blister Card - 20 G

  • Inhibits rust
  • Lubricates water pump
  • Quick permanent seal
  • Compatible w/all antifreeze including extended life coolants
  • Will not clog cooling systems

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Sold By Price
Amazon
Ace Hardware
Advance Auto Parts
Long Beach Ace Hardware

Product Details

Specifications

Details
Recommended Surface Type Aluminum
Container Size 0.7 oz
Brand Name AlumAseal
Product Type Stop Leak Radiator Sealer

Reviews From Real Customers

diver1972
Terry

16. Bar’s Leaks Cooling System Repair – 16.9 fl oz bottle

Bar's Leaks Cooling System Repair - 16.9 fl oz bottle

  • Scientifically Formulated To Stop Coolant Leaks, Thereby Reducing Antifreeze Loss
  • Cooling System Repair Stops Overheating And Reduces Water Temperature
  • Works With Any Color Antifreeze
  • Reinforced With Carbon Fiber

Check Latest Price

Sold By Price
Amazon
Walmart
AutoZone
NAPA Auto Parts

Product Details

Specifications

Details
Size 1 Pack

Reviews From Real Customers

Jeff21

17. Liqui Moly Radiator Stop Leak 250ml

Liqui Moly Radiator Stop Leak 250ml

  • suitable for aluminum radiators.
  • permanently and reliably seals hairline cracks and small leaks.
  • no negative side effects on the water pump or heating circuit.
  • for preventive use For all cooling water and heating systems with and without water filters.

Check Latest Price

Sold By Price
Amazon
MicksGarage.com

Product Details

18. Wynns WY55864 Radiator Stop Leak 325ml

Wynns WY55864 Radiator Stop Leak 325ml

  • Stops and prevents leaks in the radiator and cooling
  • Stops and prevents leaks
  • Stops head gasket leaks
  • Protects the cooling system
  • Anti-corrosion

Check Latest Price

Sold By Price
Amazon
eBay
Bonanza – roxy media’s booth
NxDeals.com

Product Details

Specifications

Details
Product Genre/Category Auto

Reviews From Real Customers

Lisahere
b348xyx

19. Fernox 57883 F4 Central HEATING Leak Sealer – 1 Pint

Fernox 57883 F4 Central HEATING Leak Sealer - 1 Pint

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Sold By Price
NorthStock

Product Details

Reviews From Real Customers

nilknarf
TristanThom
JamesB007x

20. Rislone Cooling System Radiator Stop Leak

Rislone Cooling System Radiator Stop Leak

  • Product Type: Auto Oil
  • Model Number: 41186
  • Package Weight: 450.0 g
  • Country of Origin: Australia

Check Latest Price

Sold By Price
bigamart.com

Product Details

Reviews From Real Customers

Peter
WiseGuy
Snapper

Conclusion

In general, however, a heater core leak sealant should be able to effectively seal the leak and prevent further damage to the heater core.

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