Top 10 Coolant Stop Leaks
for May 2022

Recommendations are independently chosen by MOOZ’s editors. Purchases you make through our links may earn us a commission.

1
9.8
SCORE
XADO ATOMEX Stop Leak Radiator Coolant/Antifreeze Additive - Restore Radiator Parts & Prevent Future Damage (Bottle, 250 ml)

XADO ATOMEX Stop Leak Radiator Coolant/Antifreeze Additive

Restore Radiator Parts & Prevent Future Damage (Bottle, 250 ml)

by XADO Chemical Group
What We like

Provides A Long-term Protection Of The Cooling System Against Rust And Corrosion

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Product Features

  • Best Leaking Radiator Repair Additive
  • Eliminates The Need For Expensive Repair
  • Universal Application For Gasoline And Diesel Engines Of Automobiles And Other Equipment
  • Neutral For Materials Of Cooling System Parts (Gaskets, Rubber Hoses, Aluminum, Plastic And Steel Radiators)

Neutral for materials of cooling system parts (gaskets, rubber hoses, aluminum, plastic and steel radiators) Universal application for gasoline and diesel engines of automobiles and other equipment Eliminates the need for expensive repair Best leaking radiator repair additive

2
9.7
SCORE
BlueDevil Products 00211 Coolant Stop Leak - 16 Ounce, Blue

BlueDevil Products 00211 Coolant Stop Leak

16 Ounce, Blue

by BlueDevil Products
What We like

Easy to use No flushing required

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Product Features

  • Permanent repair for all cooling system leaks
  • Safe for all cooling system components
  • Safely mixes with all types of antifreeze/coolant

Permanent repair for all cooling system leaks Safe for all cooling system components Safely mixes with all types of antifreeze/coolant

3
9.2
SCORE
K-Seal ST5501 Multi Purpose One Step Permanent Coolant Leak Repair, Blue

K-Seal ST5501 Multi Purpose One Step Permanent Coolant Leak Repair

Blue

by K-Seal
What We like

If product did not seal head gasket leak, the system might be Over-pressurized, which causes back pressure and doesn't allow the product to reach the problem area, on this page below under Technical Specification is a PDF Guide with instructions to follow to complete the repair successfully

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Product Features

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

Fixes cracks and leaks in radiator, head gasket, freeze plugs, cylinder heads, heater core, water pump casing and engine blocks Mixes with all antifreeze Permanent coolant leak repair - just shake, pour and go No draining or flushing

4
9.1
SCORE
K-Seal ST5516 HD Multi Purpose One Step Permanent Coolant Leak Repair

K-Seal ST5516 HD Multi Purpose One Step Permanent Coolant Leak Repair

by K-Seal
What We like

If product did not seal head gasket leak, the system might be Over-pressurized, which causes back pressure and doesn't allow the product to reach the problem area, on this page below under Technical Specification is a PDF Guide with instructions to follow to complete the repair successfully

more infoarrow_drop_down

Product Features

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

Mixes with all antifreeze Fixes cracks and leaks in radiator, head gasket, freeze plugs, cylinder heads, heater core, water pump casing and engine blocks No draining or flushing Permanent coolant leak repair - just shake, pour and go

5
8.8
SCORE
Certified AC Pro Car Air Conditioner Stop Leak Detector Kit, Glasses and UV Pen for Detecting O Ring or Hose Leaks, Professional Grade, 438

InterDynamics Certified AC Pro Car Air Conditioner Stop Leak Detector Kit

Glasses and UV Pen for Detecting O Ring or Hose Leaks, Professional Grade, 438

by Interdynamics
What We like

Professional grade

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Product Features

  • Includes yellow tinted protective glasses
  • Works with all types of UV leak detection dye
  • High-intensity true ultraviolet leak detection pen light
  • AAA batteries included

Aaa batteries included Includes yellow tinted protective glasses Works with all types of uv leak detection dye High-intensity true ultraviolet leak detection pen light

6
8.7
SCORE
AlumAseal ASBPI12 Radiator Stop Leak Powder Blister Card - 20 g

AlumAseal ASBPI12 Radiator Stop Leak Powder Blister Card

20 g

by Gold Eagle Co.
What We like

Safe and effective for all metal, plastic and rubber cooling system parts

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Product Features

  • Compatible with all antifreeze and coolants
  • Stop leak tube treats cooling systems up to 22 quarts (21 liters)
  • Stops leaks safely, quickly and easily
  • Will not clog cooling systems

Will not clog cooling systems Stops leaks safely, quickly and easily Stop leak tube treats cooling systems up to 22 quarts (21 liters) Compatible with all antifreeze and coolants

7
8
SCORE
Prestone AS145 Stop Leak Repair for Radiators, Heater Cores, and Hoses, 11 oz, 1 Pack

Prestone AS145 Stop Leak Repair for Radiators

Heater Cores, and Hoses, 11 oz, 1 Pack

by Prestone
What We like

Combination of natural and synthetic components provides the ability to seal leaks up to 0.020" x 0.5"

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Product Features

  • Stops the leak as well as the corrosive condition that causes it
  • Boosts corrosion inhibitors to protect against pitting and corrosion, which cause radiator leaks
  • Seals even large leaks without interfering with the flow through the radiator or heater core
  • Patented formula quickly stops leaks in radiators, water pumps, and heater cores

Stops the leak as well as the corrosive condition that causes it Patented formula quickly stops leaks in radiators, water pumps, and heater cores Seals even large leaks without interfering with the flow through the radiator or heater core Boosts corrosion inhibitors to protect against pitting and corrosion, which cause radiator leaks

8
8
SCORE
J-B Weld DS-114 PERM-O-Seal Radiator Stop Leak - 0.7 oz.

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

0.7 oz.

by J-B WELD
What We like

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.

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Product Features

  • 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.
  • 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.
  • MONEY SAVING REPAIR SOLUTION: The powered concentrate allows for an economical repair as compared to liquid based alternatives that use similar technology.

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. 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.

9
8
SCORE
AC Pro Car Air Conditioner R134A Refrigerant Stop Leak Kit, For Rubber and Metal Leaks in O Rings and Hoses, 3 Oz, MRL-3

InterDynamics AC Pro Car Air Conditioner R134A Refrigerant Stop Leak Kit

For Rubber and Metal Leaks in O Rings and Hoses, 3 Oz, MRL-3

by Interdynamics
What We like

Comes with recharge hose

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Product Features

  • Seals metal leaks in condensers, evaporators, accumulators, receiver and driers
  • Safe for all R-134A systems and recovery equipment
  • Seals rubber leaks in hoses, O-rings, gaskets
  • Compatible with all lubricants

Seals rubber leaks in hoses, o-rings, gaskets Safe for all r-134a systems and recovery equipment Seals metal leaks in condensers, evaporators, accumulators, receiver and driers Compatible with all lubricants

10
7.7
SCORE
InterDynamics Certified AC Pro Car Air Conditioner R134A Refrigerant Stop Leak Kit, for Rubber and Metal Leaks in O Rings and Hoses, 3 Oz, CERT325-6

InterDynamics Certified AC Pro Car Air Conditioner R134A Refrigerant Stop Leak Kit

for Rubber and Metal Leaks in O Rings and Hoses, 3 Oz, CERT325-6

by Interdynamics
What We like

Professional grade

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Product Features

  • Seals rubber leaks in hoses O-rings and gaskets
  • Safe for all R-134a systems
  • Comes with recharge hose
  • Seals metal leaks in condensers, evaporators, accumulators, receiver and driers

Seals metal leaks in condensers, evaporators, accumulators, receiver and driers Seals rubber leaks in hoses o-rings and gaskets Comes with recharge hose Safe for all r-134a systems

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