Table of Contents
- View The Best Radiator Stop Leak Below
- 1. Bar’s Leaks Liquid Aluminum Stop Leak
- 2. BlueDevil Hydraulic Stop Leak
- 3. AlumAseal Radiator Stop Leak Powder Blister Card
- 4. Bar’s Leaks HDC Radiator Stop Leak Tablet
- 5. Prestone Complete Care and Stop Leak
- 6. ATP AT-205 Re-Seal Stops Leaks
- 7. K-Seal ST5501 Permanent Coolant Leak Repair
- 8. J-B Weld Radiator Stop Leak
- 9. Bar’s Leaks Intake and Radiator Stop Leak
- 10. Liqui Moly Radiator Stop Leak
- Radiator Stop Leak Buyer’s Guide
A radiator leak can be a very expensive problem to fix, especially if it results in having to replace your whole radiator. Finding an incriminating puddle of liquid under the front of your car is one of the most concerning discoveries you can make as a driver.
There is a solution, however, that can fix most minor leaks and save you lots of hard-earned money – a radiator stop leak. This product will seal the source of the leak from within the radiator. This is an inexpensive way to perform a leak repair, and often, the product can simply be added to your coolant system. It will stop leaks in a matter of moments, saving you time, stress, and an expensive trip to the mechanic’s shop.
So, which is the most effective radiator stop leak product on the market this year? It can be hard to know which will work and which may just be adding fuel to the fire. That’s why we have compiled our top ten best radiator stop leaks into a handy list to help you decide which stop leak is best for you.
View The Best Radiator Stop Leak Below
1. Bar’s Leaks Liquid Aluminum Stop Leak
The Liquid Aluminum Stop Leak from Bar’s is one of the best radiator stop leaks available and is super affordable to boot. It will seal leaks many types of leaks to a very high standard, including radiator leaks, freeze plug leaks, and gasket leaks. This product will also lower your water temperature. You can use it in all coolant systems, including all colors of coolant, antifreeze, and water.
Bar’s Leaks advise that you can add their Bar’s Leaks Liquid Aluminum Stop Leak straight into your cooling system, and after adding the liquid aluminum, to idle your engine for 10-20 minutes. This will allow the product to work. The liquid aluminum usually seals leaks within a few minutes. However, large leaks may require up to 20 minutes or may need you to add another dose of the Bar’s Leaks liquid aluminum stop leak.
+ Bar’s Leaks is compatible with all coolants
+Add directly to your cooling system
+ Lowers water temperature
+ Works in up to 20 minutes
Why We Like It – Bar’s Leaks is a fantastic product – it’s one of the best versatile products and provides a great solution to a medley of different leaks. Bar’s Leaks is an excellent option for any radiator leak repair.
2. BlueDevil Hydraulic Stop Leak
This stop leak product from Blue Devil is a permanent solution to sealing hydraulic leaks. It will work in all hydraulic pump systems and is perfect for any vehicle that uses hydraulic oil. It will repair any leaks and material within these kinds of systems, including large leaks and cracks in most types of metal. The product will also help repair cracked or damaged rubber seals.
The guided ratio of product to fluid is 6Oz of stop leak to 1 gallon of hydraulic fluid for the best seal possible. Blue Devil advises that their stop leak may take longer to work than other stop leaks on the market. You’ll need a few weeks to see the full effectiveness of the product. But the results are well worth the wait, as this product creates a secure and solution that’s permanent to your hydraulic leak.
+ Permanent and effective solution
+ Repairs cracked and worn rubber seals
+ Professional standard
+ Hydraulic specific
Why We Like It – This is a good industrial option for those of you with hydraulic systems that may have a leak such as fork-lifts, tractors, and even industrial equipment such as pumps.
3. AlumAseal Radiator Stop Leak Powder Blister Card
This handy product from AlumAseal is a one of the brand’s best radiator stop leaks for practicality as they come in handy blister packs. The product itself is contained within small tubes in amounts to suit your own needs. This stop leak is suitable and safe for all metal, plastic, and rubber seals and provides fast and effective radiator stop leak repair that is compatible with all cooling systems. One tube is effective in up to 22Qtz.
The product is a non-clogging powder supplied in a small tube. It’s really simple to use. Make sure your engine is turned off and that it’s cold. Remove the radiator cap and pour the contents of the tube straight into the system, then drive a short distance to begin the sealing process. The repair will take full effect the more you drive. The formulation is also a rust preventative, which is a brilliant addition.
+Fast and effective stop leak product
+Compatible with all coolants
+Drive to seal and pours straight into the cooling system
+Rubber safe radiator sealant
Why We Like It – Not only is this radiator stop leak practical and easy to use, but it will also prevent rust, and it’s safe with all cooling systems.
4. Bar’s Leaks HDC Radiator Stop Leak Tablet
This is another fantastic leak stopper for radiator issues from Bar’s Leaks, this time in a nifty tablet form. This radiator leak stop seals your cooling system, combats electrolysis, stalls the build-up of rust and corrosion on the metal components, and will even provide lubrication for your water pump seals. It also neutralizes the PH levels within your cooling system or radiator, preventing scale.
This product has actually been used on OEM production lines for over three years and is the product of extensive research and formulation by industry professionals. It’s also pretty unique in that it’ll stop your oil from being contaminated with coolant. It’s also safe to use on gaskets and heater cores.
+Effective on external and internal radiator leaks
+Seals oil to coolant leaks
+Safe for gaskets, aluminum, and heater cores
+Proffesional grade and industry-approved
+Offers rust prevention as well as radiator sealant
Why We Like It – This radiator stop leak is actually in use on assembly lines as a leak and rust preventative. It’s safe on all parts of your cooling system and heater core.
5. Prestone Complete Care and Stop Leak
This radiator stop leak from Prestone is one of the more effective radiator stop leak products around for functionality. It has been formulated using polymer technology and helps to lubricate and sustain the life of your water pump. It stops leaks in all of your major cooling system parts and also helps to fight corrosion and rust. As well as all this, it works with just one use when added straight to your cooling system or radiator.
It’s easy to use and safe for all coolant types, including antifreeze and straight water. Make sure you shake the bottle and apply directly into the coolant well. Reviewers have confirmed that it works pretty much immediately and gives effective results – it will make sure that you have a fairly permanent coolant leak repair. Make sure you apply it to a cold engine or radiator for it to effectively seal leaks in the best way.
+Very effective radiator stop leak that fixes leaks quickly
+Safe for most engine components and fast-acting
+Lubricates water pump
Why We Like It – Not only is the coolant leak repair fast and effective but this stop leak is one of the best radiator stop leak compounds for versatility, due to its advanced formulation.
6. ATP AT-205 Re-Seal Stops Leaks
The AT-205 re-seal from ATP automotive is a professional grade stop leak radiator sealant that is safe for all rubber seals and gaskets. It can be added to most systems in your car, including your cooling system, engine, steering pump, heater core, and any hydraulic systems, making this one of the best radiator stop leak compounds available for sheer versatility and cost-effectiveness.
ATP at-205 Re-seal is oil safe and can be used with conventional and synthetic oil, including gearbox oil, hydraulic oil, and power steering fluid. The stop leak will also not corrode, break down seals or cause them to over swell due to the formula being made without harmful petroleum compounds. You are safe to add the product straight to your cooling system and seals leaks within 5 hours.
+One of the most professional radiator stop leaks
+Safe for power steering systems and your heater core
+Will seal leaks in a matter of hours
+Can be used in a hydraulic system
+Safe for all engine components
Why We Like It – ATP at-205 radiator stop leak is versatile fast-acting and safe for most components, can treat your cooling system, heater core, power steering, and radiator, and it’s also oil safe.
7. K-Seal ST5501 Permanent Coolant Leak Repair
If you’re looking for a serious permanent radiator leak solution, then this product may be the best stop leak to buy for a high and lasting standard. This product is the only radiator stop leak to be tested to meet ASTM D3147 conforming standards and is safe for all cooling systems as well as gaskets and seals, and also aluminum and plastic heads on old and new engines.
The radiator repair will seal any cracks within minutes of use in your cooling system, using its microfiber technology that will bond and weave over any leak or fracture. You can simply pour and go, safe in the knowledge that your radiator is well on its way back to full health. This brand of radiator stop leaks also has a rejuvenating factor to the compound that will bring life and protection back to rubber seals and gaskets.
+Tested to the highest standards to prove the effectiveness
+Works within minutes of application
+Safe on aluminum and plastic heads
+Safe for all cooling systems and coolant types
Why We Like It – This product has been tested and approved to industry standards and is an all-around leak fix, preventative, and also a part protective solution to fix your coolant system or radiator.
8. J-B Weld Radiator Stop Leak
This handily packaged radiator stop leak is a great and inexpensive product from J-B weld that will provide you with an effective solution to leaks within your radiator. It gives you a permanent repair to small fractures and leak spots and also boasts an effective lubricating property. It also has rust prevention and corrosion inhibiting properties, too, that will help to protect your radiator in the future.
You can add the stop leak straight to your cooling system, and it’s safe for all coolant types in all vehicles. It will get to work quickly to patch up any leaks in your radiator as you drive. The stop leaks formulation is specially designed not to clog your cooling system and also to be friendly to your engine and any other system in your engine bay. The product is, however, not intended for use with oil or hydraulics.
+Very cost-effective so will save you a lot of money on repairs
+Fast acting and very simple to use, and a permanent solution
+Rust and corrosion inhibitors within the compound
+Water lubrication so will help the components of your radiator
+ Works as you drive so no need to sit and idle after use
Why We Like It – This is a very inexpensive option, so it is perfect for small radiator repairs. It will save you money and provide lasting protection to help prevent future issues in your engine components.
9. Bar’s Leaks Intake and Radiator Stop Leak
This is yet another brilliant product from Bar’s Leaks, this time, their liquid copper intake and radiator stop leak. This is a brilliant product for larger leaks within your cooling system, and for your intake. This stop leak will repair radiator and heater core leaks and freeze plug leaks. Bar’s Leaks even boast the ability also to be able to fix blown head gaskets that may be leaking oil and coolant, as well as intake manifold leaks.
The radiator stop leak itself is inexpensive, so even though it’s recommended to use one bottle in your engine, it won’t break the bank to do so and will prevent you from needing some costly repairs. The stop leak product utilizes an antifreeze safe silicone compound that will bond to the leak and won’t require you to drain the radiator or cooling system, providing fast ease of use and a DIY fix.
+ Can use it for lots of engine leaks including radiator, gasket head unit and cooling system leaks
+ It’s a natural lubricant. Can help prevent corrosion and wearing of parts from poor lubrication
+ Seals big leaks and well as fractures and small holes
+ A great stand-in solution for engine repairs if you can’t afford to go to a shop immediately
+ Antifreeze safe compound that can simply be put in and allows you to drive off immediately.
Why We Like It – It’s great for more serious repairs, and seals leaks not just in your radiator. Although it’s not a permanent solution to head damage, it will keep your car going safely until you can take it in for a replacement or rebuilding, giving you time to prepare for a repair without worrying about being without your car.
10. Liqui Moly Radiator Stop Leak
This is another one of the best radiator stop leak products around, and though it may be the last product we’re reviewing, it is by no means the least! This stop leak seals radiator leaks with immediate and permanent effect. The stop leak itself is straightforward to use. It will seal your combustion chamber as well as your radiator to prevent contamination of the coolant.
This can be used in all cooling systems, whether they have a filter or not. It’s the perfect stop leak for sealing hairline fractures, small gashes, and cracks or points of impact damage from stones. It works as you drive, so you can use it and see the results immediately. There will be no more puddles of liquid under your car, and any smoking you may have been experiencing will stop. Your radiator will have been fixed.
+Easy and fast to use with immediate and noticeable effects
+Perfect for small and fast repairs, saving you time and money
+Safe in all coolant and radiator types and engine safe too
+Stops contamination within your engine
+Simply drive to seal
Why We Like It – This stop leak has pretty much immediate effects, and it is safe for use in all systems and situations. It’s non-clogging and is great for small, quick repairs of fractures and chips.
Radiator Stop Leak Buyer’s Guide
Hopefully, our top 10 best radiator stop leak reviews will help you on the way to purchasing the correct product for your needs. However, you likely still have a fair amount of questions. A stop leak is a complex and versatile solution, and it can be hard to know just exactly what it is, how to use it and what you might need, and whether, ultimately, it’s going to work for you and be safe in your engine.
To help you answer these questions and more, we’ve compiled this helpful consumer guide. Read before making your purchasing decision to make the best-informed choice that you can as a consumer!
What is Radiator Stop Leak?
Radiator stop leak is a product that will seal fractures and cracks, either external or internal, within your radiator or other systems in your engine, depending on the product in question. They are designed to bond to the metal, rubber, or plastic within your cooling system. They seal the source of the leak without the need for replacing components or having extensive mechanical investigation and repair.
Stop leak generally comes in a liquid or powder form that can be added straight to the coolant for immediate effect.
They can also be used for protection and prevention, and a lot contain anti-corrosion and rust inhibitors that may also rejuvenate your rubber seals and metals.
Radiator stop leaks are versatile and can provide great permanent or temporary fixes, depending on your needs. They are available for a wide range of issues and different uses.
What is a good radiator stop leak?
When deciding whether a stop leak is good or not, there are a few factors to consider. First, is whether it’s a permanent or long-lasting solution. This is important, as a repair that only lasts a few days is probably not helpful to you. Not being permanent doesn’t necessarily mean that it’s a bad product, as some leaks are so large you will have to go to a mechanic anyway, but a good stop leak will keep your car going until you can do that.
Another thing to consider is whether it’s safe for oil, too. You may not have an oil or head unit leak. However, the coolant leak may be in a place that could contaminate the oil, so you want to make sure the product is safe to come into contact with oil. This is a big possibility within your engine, especially as there might be further leaks that you may be unaware of.
You also need to make sure that the stop leak is safe for rubber and gaskets as it’s sure to come into contact with theses when it circulates your cooling system.
Is a radiator stop leak a good idea?
For small cracks and leaks, a radiator stop leak is a great idea. It can be a permanent solution and save you an awful lot of money in the long run. Often for small leaks, a mechanic will simply use stop leak anyway but may charge you a lot more than buying it yourself.
For larger leaks, radiator stop leak can still be a pretty good bet for your repairs, as a lot of the products that we have reviewed are professional-grade and capable of dealing with large cracks or splinters. Even if it’s not a permanent solution, it can be a fantastic lifeline if you cannot afford to take your car into the mechanic shop immediately. The stop leak will keep your engine ticking over safely and prevent worsening issues until you can get the leaks repaired or the parts replaced.
However, if the problem persists or worsens after using a stop leak, then you have an issue that does need to seek professional mechanical attention, and it’s best to take the vehicle into the shop for repair or replacement of parts. So be sure to keep an eye out after using the recommended amount of stop leak.
Will Stop Leak harm my engine?
Put simply, no. However, it’s important to make sure you are buying the correct product for your needs, as not all radiator stop leaks are fully engine-safe in every capacity.
Some stop leaks are solely intended for use in the coolant system and are not formulated to be safe in the head unit or other engine components. So if your leak is coolant to oil, this will not work for you, as it may cause further damage or simply not bond effectively and, as such, not repair the leak.
The good news is that many are completely versatile and safe for your engine. Some, such as Bar’s leaks liquid copper that we reviewed at the number nine spot, are marketed towards use in lots of different systems. This means it’s very much safe for your engine and even able to provide leak sealant for things such as your head gasket or power steering pump.
How do I use a radiator stop leak?
All of the stop leaks that we have reviewed in our list are pour and go, or add and go, meaning you just add the stop leak directly to the component that’s leaking. It will then get to work as you idle or drive, meaning you can use your vehicle straight away, and you will not have to drain your coolant system.
This method is straightforward to do at home. For radiator repairs specifically, undo the radiator cap, pour in the recommended amount of product (be sure to read the instruction for your specific product carefully), and then replace the cap. Either idle your car for 10-20 minutes or go for a short drive, depending on the product’s recommendation.
For other types of system leaks, make sure you refer to the product instructions. You may need to apply the stop leak straight into the coolant reservoir or another fluid reservoir in your engine bay. For power steering, hydraulic, or coolant to oil leaks, follow the specific instructions carefully to make sure that you seal your leak effectively and to the best effect of the product.
What kind of stop leak do I need?
The first step is to identify what sort of leak you have. If you are finding puddles of coolant near the front end of your car, then you likely have a radiator leak or a leak within the cooling system. For this sort of leak, you can use any radiator stop leak that you feel suits you best, with the absolute best radiator stop leak products on the market listed above to make things even easier for you,
If there is white or blue smoke coming from your exhaust, then it’s likely you have an oil leak or coolant to oil leak. This could be a simple crack in the cooling system that’s allowing coolant to get into the oil and burn off, causing the smoke to appear. Alternatively, it’s a symptom of a blown head gasket.
For a coolant-to-oil leak, choose a product that can cope with repairing this sort of seal issue. The K-Seal ST5501 Permanent Coolant Leak Repair is a great option for this, as it’s designed to seal these kinds of leaks within your system.
For a head gasket leak or blown head gasket, Bar’s leaks liquid copper intake and radiator stop leak is a good bet, as it is professionally and exclusively formulated to seal leaks and repair damaged head units. For small amounts of damage, it’s perfect for providing what may be a permanent fix and seal.
However, it’s important to note that Bar’s states that, for serious head damage, melted head units or completely blown gaskets, it’s not a permanent repair and that you should seek advice from a qualified professional. Running your car with a damaged head unit can cause serious ongoing issues or engine failure.
The product, however, can provide a perfect interim fix if you can’t afford to fix your car immediately and need to keep it running. This is especially useful for those with modified or remapped cars that may require an expensive top end rebuild or uprated replacements to be able to save up for this work,
Can stop leak fix all leaks in my engine?
There are many different types fo stop leak that can fix a range of issues from a simple coolant leak to power steering to gearbox leaks. There is almost definitely a stop leak that can solve the issue you have. However, you must diagnose the leak correctly to ensure that you buy the best radiator stop leak for your needs.
Once you have figured out the source of your leak, you should be able to find a suitable product on our handy list that will seal the leak your car has developed.
Overall, it may be overwhelming to start the plunge into stopping leaks and finding which one is best for you. But, hopefully, our reviews and consumer guide will help you make the best decision you can and get your car back in full running order as quickly as possible.