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The 12 Best Radiator Stop Leaks in 2023

If you're ever experiencing a radiator stop leak, the first thing to do is take a look at your system for any potential causes. If you find that the radiator is leaking liquid, then it's likely that something is blocking the narrow passages vital to the proper circulation of coolant. By inspecting and repairing any of your system parts as needed, you can help to stem the flow of liquid out of your cooling system without having to block those passages so vital to the proper function.

Lumia Shaffer
  Oct 2, 2023 11:12 AM
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Top Picks

Best Overall:Liqui Moly 20132 Radiator Stop Leak
(Sealed combustion chamber from damages caused by coolant admi. Leak protection for your engine. Quick and easy leak prevention)
Best Budget:Bar's Leaks HDC Radiator Stop Leak Tablet
(Bar's Leaks HDC Radiator StopLeak Tablet helps to prevent rust and corrosion. Leaks are caused by a variety of factors, including bad design, poor construction, and corrosion from the elements)

Editor's Choise:Prestone AS195 Complete Care and Stop Leak
(Reduces friction and protects against corrosion. Helps in just 1 tune. Formulated with patented Grafted Polymer Technology)

Related post

Comparison Table

Showing  1 - 10  in  12 results
RANKING LIST  |  SORT BY SCORES
TOP Choice
1
Genuine GM (12378255) Fluid 3634621 Cooling System Seal Tablet - 4 Grams, (Pack of 5)
Genuine GM (12378255) Fluid 3634621 Cooling System Seal Tablet - 4 Grams, (Pack of 5)
View on Amazon
  • SCORE
    9.2
    AI Score

    Reviews are based on big data aggregated from sales pages and product buyer reviews. All ranking arrangements are automatically AI-driven according to product buyer reviews.

  • Brand
    Genuine GM
Customer Reviews

Non-toxic

DEX-COOL compatible

Engine application is based on liters of volume in cooling system

Formulated for automotive use

For use with all vehicles

2
ACDelco GM Original Equipment 10-108 Cooling System Sealing Tabs - 4 g (Pack of 5)
ACDelco GM Original Equipment 10-108 Cooling System Sealing Tabs - 4 g (Pack of 5)
View on Amazon
  • SCORE
    9.0
    AI Score

    Reviews are based on big data aggregated from sales pages and product buyer reviews. All ranking arrangements are automatically AI-driven according to product buyer reviews.

  • Brand
    ACDelco
Customer Reviews

Engineered for use on a variety of engine components - effective on: oil pan, ladder frame, front and rear covers, t-joints, manifold corners, intake, manifold end seals, and cam covers

Designed for quick and easy application, assembly may be filled with oil or coolant immediately after applying sealant and torqueing the bolts

High viscosity product that cures when exposed to air

3
C and R Racing Radiators 59-00001 Dike Stop Leak, 1 Pack
C and R Racing Radiators 59-00001 Dike Stop Leak, 1 Pack
View on Amazon
  • SCORE
    8.8
    AI Score

    Reviews are based on big data aggregated from sales pages and product buyer reviews. All ranking arrangements are automatically AI-driven according to product buyer reviews.

  • Brand
    C and R Racing Radiators
Customer Reviews

Can prevent a DNF in the event of a radiator puncture, cracked cylinder head, or head gasket Problem

After extensive research, C & R racing has found a stop leak that doesn't leave a residue

C&R Stop Leak stays suspended in the water so that when the water is drained, all of the stop leak is drained with the water leaving no residue

Package Weight : 1.2 pounds

4
Liqui Moly 20132 Radiator Stop Leak, 0.25 l, 1 Pack
Liqui Moly 20132 Radiator Stop Leak, 0.25 l, 1 Pack
View on Amazon
  • SCORE
    8.6
    AI Score

    Reviews are based on big data aggregated from sales pages and product buyer reviews. All ranking arrangements are automatically AI-driven according to product buyer reviews.

  • Brand
    Liqui Moly
Customer Reviews

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

5
Bar's Leaks 1109 Block Seal Liquid Copper Intake and Radiator Stop Leak - 18 oz.
Bar's Leaks 1109 Block Seal Liquid Copper Intake and Radiator Stop Leak - 18 oz.
View on Amazon
  • SCORE
    8.6
    AI Score

    Reviews are based on big data aggregated from sales pages and product buyer reviews. All ranking arrangements are automatically AI-driven according to product buyer reviews.

  • Brand
    Bar's Leaks
Customer Reviews

Seals larger leaks seals

Repairs heater core leaks

Repairs freeze plug leaks

Repairs blown head gaskets

Repairs blocks

6
K-Seal ST5501 Multi Purpose One Step Permanent Coolant Leak Repair, Blue
K-Seal ST5501 Multi Purpose One Step Permanent Coolant Leak Repair, Blue
View on Amazon
  • SCORE
    8.4
    AI Score

    Reviews are based on big data aggregated from sales pages and product buyer reviews. All ranking arrangements are automatically AI-driven according to product buyer reviews.

  • Brand
    KALIMEX LTD
Customer Reviews

Permanent Coolant Leak Repair - Just Shake, Pour And Go

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

7
Bar's Leaks PLT11 Pelletized HD Radiator Stop Leak - 11 oz.
Bar's Leaks PLT11 Pelletized HD Radiator Stop Leak - 11 oz.
View on Amazon
  • SCORE
    8.4
    AI Score

    Reviews are based on big data aggregated from sales pages and product buyer reviews. All ranking arrangements are automatically AI-driven according to product buyer reviews.

  • Brand
    Bar's Leaks
Customer Reviews

Seals leaks

Conditions cooling system

Inhibits rust and corrosion

Lubricates water pump seals

Helps control electrolysis

8
Bar's Leaks HDC Radiator Stop Leak Tablet - 60 Grams
Bar's Leaks HDC Radiator Stop Leak Tablet - 60 Grams
View on Amazon
  • SCORE
    8.4
    AI Score

    Reviews are based on big data aggregated from sales pages and product buyer reviews. All ranking arrangements are automatically AI-driven according to product buyer reviews.

  • Brand
    Bar's Leaks
Customer Reviews

Seals leaks

Conditions cooling system

Inhibits rust and corrosion

Lubricates water pump seals

Helps control electrolysis

9
Bar's Leaks 1196 Radiator Stop Leak - 11 oz. , Grey
Bar's Leaks 1196 Radiator Stop Leak - 11 oz. , Grey
View on Amazon
  • SCORE
    8.4
    AI Score

    Reviews are based on big data aggregated from sales pages and product buyer reviews. All ranking arrangements are automatically AI-driven according to product buyer reviews.

  • Brand
    Bar's Leaks
Customer Reviews

Works with all types and colors of anti-freeze coolant

Stops and seals coolant leaks

One bottle treats up to 4 gallons

Works with all types and colors of anti-freeze coolant

Stops and seals coolant leaks

One bottle treats up to 4 gallons

10
Prestone AS195 Complete Care and Stop Leak - 22 oz.
Prestone AS195 Complete Care and Stop Leak - 22 oz.
View on Amazon
  • SCORE
    8.4
    AI Score

    Reviews are based on big data aggregated from sales pages and product buyer reviews. All ranking arrangements are automatically AI-driven according to product buyer reviews.

  • Brand
    Prestone
Customer Reviews

Extends and protects water pump life

Formulated with patented Grafted Polymer Technology

Reduces friction and protects against corrosion

Helps in just 1 treatment

Also stops and prevents leaks in all major cooling system components

Last update on 2023-10-02 / Affiliate links / Images, Product Titles, and Product Highlights from Amazon Product Advertising API

4.8
4 ratings

FAQs

How many times can you use stop leak in a radiator?

You can use stop leak in a radiator multiple times.

How much stop leak should I use in my radiator?

There is no one definitive answer to this question. Some people recommend using 1 2 bottle of stop leak for every 4 engine cylinders, while others recommend using less than 1 bottle. Ultimately, the amount of stop leak you use will depend on your radiator's specific design and construction.

How long will radiator Stop leak work?

One common problem with radiators is that they can start to leak water over time. This can cause your car to run a little bit cooler, but it's also a big safety risk. To be safe, you should replace your radiator as soon as possible if it's been leaking water for more than 50,000 miles.

Does radiator stop leak hurt your engine?

There is no risk of damage if the radiator stops leaking.

Can you fix a radiator leak without replacing it?

Yes, you can fix a radiator leak without replacing it. A few common repairs to a leaking radiator are temporary fixing the leaks with a hot water bottle or some other liquid, filling the radiator with new water, and re-flushing the system.

Conclusion

Radiator stop leak is designed to stem the flow of liquid out of your cooling system without blocking those narrow passages so vital to the proper circulation of coolant. This will help reduce noise and make your system more efficient.

Lumia Shaffer
Lumia Shaffer

I'm Lumia Shaffer! I'm a Kirby Research author, with a passion for writing, I've researched and published many in-depth product research articles!
My Twitter: https://twitter.com/KirbyLumias