Best Epoxy for Plastic Radiator Repair [Reviews & Buying Guide]

The radiator is the key asset to maintain the engine’s health. It automatically reduces the temperature when the engine becomes hot. But a malfunctioned radiator may fail to do its regular performance. Leakage in the radiator is prevalent type of malfunctioning.

If the radiator is made of metal, you can repair it through a metal galvanizer or welder. But it is like imagination to weld a plastic surface with welder. It can melt the plastic easily. So, what will you do to repair plastic radiator?

best epoxy for plastic radiator repair

We have brought up an idea to work, named the “best epoxy for plastic radiator repair”. It can repair the plastic radiator cracks. It takes less time to cure and prepare the device for reducing the heat. It works like gum or sticky glue on the plastic surface. Water, heat, or fire cannot damage the epoxy repaired device.

KwikWeld Quick Setting Steel Reinforced Epoxy
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Coolant Leak Repair
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PlasticWeld Plastic Repair Epoxy Putty
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Epoxy Putty Stick
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Best Epoxy for Plastic Radiator Repair

Finding or choosing the right epoxy among hundreds of brands or items can be tiresome. Low-quality or ordinary epoxy or putty may not repair the radiator fully. Even there may appear leakage later after you use them. Using glue or duct tape on the crack is also frustrating. So, you should always prefer the best epoxy for plastic repair.

We have worked with multiple plastic radiator repair epoxy and found a couple of them superior and reasonable. This plastic radiator repair kit review consists of those efficient products. Let us see!

J-B Weld 8276 KwikWeld Quick Setting Steel Reinforced Epoxy

J-B Weld 8276

You may think of how to weld a plastic radiator. But the reality is you cannot weld a plastic thing. However, if you use J-B Weld KwikWeld on the radiator’s body gaps, there will be no worry of welding.

J-B Weld’s experienced hands have made this fast steel reinforced epoxy. Its remarkable features can save time and money both without changing the plastic radiator or other things. Read these:

Improved formula:
8276 putty is formulated with the upgraded version of the Original Cold Weld double epoxy system. You can drill, tap, fill, mold, and sand over the surface where apply the epoxy. Hence, the formula will protect the surface from getting reparations.

Quick apply and cure time:
You can mix the tube at a 1:1 ratio to use the putty within 6 minutes only. The cure time is in between 4-6 hours. After applying it, the cure color will be dark grey.

High resistance:
It has got up to 3127 PSI tensile strength. The repaired spot can remain secure and locked under 230°F. Besides, water, petroleum, chemical, acid cannot harm this steel-reinforced epoxy.

Adaptable renovation:
You can cure the damages of metal, plastic, PVC, wood, concrete, and many more surfaces. This HD epoxy gives an ultimate performance, quality, and long-lasting results.

  • An exclusive formula can heal the nooks and crannies within moments
  • 1:1 mix ratio with 6 minutes application and 4-6 hours cure time
  • Protects plastic radiator from heat, water, chemical etc.
  • It does not get sufficient hard like other J-B Weld epoxies

K-SEAL Coolant Leak Repair

K-SEAL Coolant Leak Repair

Do you want a fast automobile coolant leak repair kit? You probably have used several crack sealants to prevent the leakage. But K-Seal ST5501 of 8oz will stop the crack or pinholes to grow more.

Its multipurpose formula keeps the plastic radiator, gasket, water pump, heater core, etc. preserved and secured. Know these attributes of this excellent leak repair for more benefits:

Special way of application:
Unlike other sealants or epoxy of plastic radiator repair, it has a unique way to use. You need to shake and add the epoxy to the radiator or overflow. Then turn on the engine and see magic. That is it.

Quick and robust formula:
The modern formula of this plastic epoxy helps to mix with any antifreeze. It can weld or seal the radiators as well as hard plastic pieces. It can stay healthy and withstand against heat and cold.

Proven result:
The block repair can cover 1/32″ holes as scientific evidence shows. It will permanently protect the leaking radiator, freeze plug, heater core from high pressure and extreme heat.

Friendly customer service:
You can read the instructions that come with the package. Besides, the customer support is always ready to give you proper assistance.

  • Suitable for DIYers and professionals
  • Pour and Go application method saves time
  • Repairs 1/32″ holes of versatile surfaces like radiator, freeze plug, heater etc.
  • Gratifying customer support
  • It may clog the radiator & heater in some rare conditions

J-B Weld 8237 PlasticWeld Plastic Repair Epoxy Putty

Plastic Repair Epoxy Putty

Time-saving application and reliable bonding – you get these two significant benefits from the J-B Weld 8237 PlasticWeld epoxy putty. It is distinctively formulated to work on plastic surfaces.

It can repair, rebuild the old structure before leakage. Besides, you will get these functional benefits from the tiny epoxy for the plastic radiator:

Affordable and readily available:
J-B Weld’s products are mostly cheap and available at the stores like 8237. It quickly works on ABS, PVC & CPVC pipes, and plastics. Again, NSF certified this product that is also applicable in contact with drinkable water.

Simple to apply:
It comes in small 2 oz. pack. First, you need to cut the pack and bring some putty out. Then, knead it with your finger and apply steadily.

Fast cure and setup time:
It is a good DIY and home-use epoxy for plastic repair. It takes 25 minutes set time, and after 3 hours cure time, the cure color will be off white.

Long-lasting result:
It can withstand against 250-300°F heat. After curing, you can drill, mold, shape, and the fixed spot. It has a strength of 600 PSI. So, you will surely get a brilliant cure for plastic tank or radiator holes.

  • Requires no extra tools or mixing tools to apply
  • You can set it in 25 minutes and get cure within 3 hours
  • NSF certified putty for plastic can resist up to 300°F
  • 600 PSI strength level
  • May not work on some plastics

Permatex 84145 Permapoxy Black Plastic Weld

Permapoxy Black Plastic Weld

Permatex 84145 Permapoxy is tiny in size but mighty in performance. This black plastic weld can bond or seal a wide range of plastics.

This quick-dry epoxy provides an excellent barrier against heat and cold to keep your engine on. Not only plastic radiator sealing but also there are more benefits to this product like these:

Strong bonding:
Fantastic adhesive can seal the fissures or pinholes on different plastic made things. Once you apply it, it will create strong bonding that never tears, breaks or melts.

Permanent epoxy repair:
The massive tensile strength of 3500 PSI maximum can protect your motor radiator active and leakage-free. The permanent epoxy repair gives lifetime time and money saving options.

Quick gelling and fixturing: You can apply it within 5 minutes and start curing the voids within just 10 minutes. It means you are ready to use the radiator soon.

Versatility of applications:
It can quickly fill gaps up to 0.125″ in diameter. This is the same on different surfaces like composites, ceramics, wood, etc.

  • 3500 PSI tensile strength
  • Permanent epoxy for plastic radiator repair
  • 5 minutes set and 10 minutes cure time
  • Repairs leakage of 0.125″ diameter
  • It may release a chemical smell when mixed

J-B Weld 2120 Radiator and Plastic Repair Kit

J-B Weld 2120

If you want to repair the plastic radiator’s hole or cracks as fast as possible, you would probably to cover up with any putty or epoxy near your hand. But J-B Weld plastic radiator repair should be there instead of ordinary fix kits.

It is made in professional ways to fight against heat and water. You would love to know the traits of this 2120 radiator and plastic repair kit:

Expert manufacturer:
J-B Weld is well-known for its different repair and maintenance products. They are serving the market for more than 40 years. So, you can trust the J-B Weld 2120 epoxy for a plastic radiator.

Easy to apply:
It does not necessitate any removal of tank or radiator. This handy dandy epoxy kit can be mixed inside the bag of packages. Burst the pouch’s center seam. Then mix and knead the putty inside the bag.

Vast application:
If you buy J-B Weld best epoxy for plastic radiator repair, it will give you flawless results. You can use this heat resistant putty to repair hole up to 3/8″ or long crack of 4″ in diameter.

It will never melt due to water or any liquid. You can apply it on a versatile surface of the repair. Plastic radiator, washer tanks, water tanks, composites, PVC, etc. holes or cracks can be fixed with 2120 JB Weld epoxy.

  • Multipurpose high-quality epoxy for leakage and cracks repair
  • Extremely heat resistant and waterproof product
  • Repairs hole up to 3/8″ and crack up to 4″ in diameter
  • Different helpful tools & accessories included
  • Sometimes it may get hot faster

Blue Magic 6522K QuikSteel Plastic Tank Repair Kit

Blue Magic 6522K

Due to extreme heat, bad weather, or unwanted accidents, plastic radiators near the engine get a leak, fractures, etc. The fast 1-hour cure of the Blue Magic 6522K Quiksteel plastic tank repair kit can amaze you sorting all problems out.

This professional-grade plastic repair and bonding kit offer vigorous results on different surfaces. You would feel relax when you apply it to the damaged spot. More about this product is here:

Professional grade:
Blue Magic 6522K works on both metal and plastic tanks, radiators, etc. It has been used in different circumstances like an automobile, home, commercial, farm, marine, etc. It comes directly from the USA.

Fast result:
It takes only 4-5 minutes to apply correctly on the drips and cracks. But it gives a fast 1-hour cure for longtime protection.

Simple application:
You can get a 2 Oz size pack, which can be mixed into a 1:1 ratio. It gives excellent safeguards if you set it up underwater. The color of the cure is off white on plastic, gray on metal.

Extreme resistance:
It has a strength of up to 5950 PSI. The sealant can resist heat up to 500°F or 260°C. Even the adverse cold weather cannot harm if it is up to -90°F or -68°C.

  • Suitable for metal and plastic surface
  • It takes 5 minutes to apply but cures within one hour
  • It has a strength of 5950 PSI with heat resistance of 500°F
  • It includes necessary tools in the package
  • Not so much satisfying result of applying the epoxy on the metal surface

Yanyi Repair Epoxy Glue Plastic

Yanyi Repair Epoxy Glue Plastic

Yanyi repair epoxy comes in a stick to repair the different metal, plastic, glass, ceramic, etc. It is a right product for quick and easy fixes of cracks.

Many homeowners and professionals use it for blocking the caves and crevices. It has some notable and extraordinary features like the below ones:

High adhesiveness:
This dark green putty stick is enough for repairing the tiny breaks, holes, or crevices. The high gluiness can work within the temperature of -50°F to 120°F.

Easy application:
There is no need to cut or size the putty. It comes in a pack of 6x5g so that you can fill the targeted spot with an equal amount.

Fast fixes:
It takes 10 minutes to set after you knead it. After the next 24 hours, the damaged spot will be cured as the putty gets hardened and permanently glued.

Excellent performance:
You can quickly fix the plastic radiator, pipes, water or fuel tanks, glass, ceramics, stone, etc.

  • Stay strong against heat, water, corrosion etc.
  • Sticks strongly to the spot within temperature range of -50°F to 120°F
  • 10 minutes set and 24 hours cure time
  • Comes in 6x 5g pack individually
  • You may feel the smell of putty unbearable

J-B Weld 8297 HighHeat 550 Degree Epoxy Putty Stick

550 Degree Epoxy Putty Stick

With up to 500°F heat resistance, J-B Weld 8297 epoxy putty stick is designed to heal and rebuild your plastic radiator’s old cracks. It can work on exhaust pipes, mufflers, motor radiators and many more.

You can use this HighHeat epoxy in DIY or industrial purposes. However, take a quick look at the intriguing features of this stick epoxy radiator:

Industrial grade:
You can mix the two-part putty with your bare hands. Again, this is suitable for DIY, home, and industrial-grade repairs of leakage of plastic tools.

Minimal cure and set time:
It takes 60 minutes to set and 8 hours to cure. After 8 hours, the result will be long-lasting. The cure color of HighHeat is machine grey.

High heat resistance:
It has a tensile strength of 800 PSI at room temperature and 600 PSI at 400°F. However, it can bear up to 450°F continuous heat and 500°F sporadic heat.

Fast application:
This three-times stronger putty is very simple to use. You need to bring out the required amount of epoxy. Then knead it with fingers and firmly stick it to the dented spot.

  • Two-part hand mixable putty for home and industrial uses
  • 60 minutes set and 8 hours cure time
  • Up to 800 PSI tensile strength and 500°F heat resistance
  • May smell like a burnt chemical

Epoxy for Plastic Radiator Repair Buying Guides

You should look a couple of factors when you want to buy the best quality epoxies. Do not miss out to care these below features in your selected product:

Temperature resistance:

If the epoxy can not tolerate the engine’s heat or nearby environment, it will melt or bend soon. The result of this situation can be life-threatening. So, you should look at some epoxies that have heat resistance within -50°F to 350° in average.

Water resistance:

The epoxy must be waterproof or water-resistant. Its because you may apply it on plastic, PVC, metal, fiberglass, wood etc. surfaces. There may be chances of water like the radiator. The select sealant should stay fit against the water or any other liquid chemicals.

Set, fixture, and cure duration:

Suppose you are about to cook something delicious. But it is taking more extra hours than you thought. The whole thing will be frustrating. Similarly, the set, fixture, and cure time of epoxy should be user-friendly and possibly shorter. Usually, stick epoxies have the least set and cure duration.

Versatility and ease of use:

Best epoxy for plastic radiator may offer versatile ways of applications. Some of these are only for plastic surfaces. Some may work on other surfaces like metal, glass, wood, etc. So, you should make a decision which one you are going to buy. Moreover, the item should be easily applicable.


Usually, there are two types of epoxy you may find at the market. Single-step epoxies are easy to use; tear the pack, cut, knead, and apply it directly. Double step epoxies have resin and hardener, available in separate packages. You will need to mix them before you use.

How to Repair Plastic Radiator Crack?

You can quickly repair the plastic radiator crack following these steps:

  1. Tear the epoxy kit and bring some putty out.
  2. Cut the putty to the required amount (if not available in even size)
  3. Knead the cut putty with fingers
  4. Gently press the putty repair onto the spot

Final Verdict:

The right decision can save your life. If the plastic radiator leaks and epoxy fails to seal it, the vehicle you are riding can be deadly to all the passengers. You should keep the engine cool by repairing instead of changing the radiator frequently.

This best epoxy for plastic radiator repair review will be productive if you pick any of these mentioned products. We have compared and studied them among hundreds to present you with the right products. Our recommendation would be the selection of double-step epoxies.

Have a safe day!

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