Plastic radiators have become increasingly common in modern vehicles, but over time they can develop small cracks or leaks that need repair. Thankfully, there are several effective options for repairing damaged plastic radiators without requiring a full replacement.
Why Choose Epoxy for Plastic Radiator Repairs?
Two-part epoxy putties and adhesives are a popular and effective solution for repairing cracks, holes, or leaks in plastic radiator tanks and components. Here are some key benefits of using epoxy for these repairs:
- Strong and Durable: Epoxy bonds form a rigid, durable material that can withstand high temperatures and pressures inside the radiator system. This provides a long-lasting, reliable repair.
- Bonds Plastic: Many epoxies are formulated to effectively bond to plastic materials, including the plastic polymer used in most radiator tanks.
- Withstands Automotive Fluids: The cured epoxy is resistant to coolants, antifreeze, oils, and other fluids used in vehicle radiator systems.
- Easy to Apply: Epoxy putties can be molded and shaped as needed to fill cracks or holes. The putty consistency makes application easy.
For these reasons, a high-quality epoxy product designed for plastic radiator repair is one of the best material options for permanently patching cracks, pinholes, or other damage.
Review of the Best Epoxy Products for Plastic Radiators
J-B Weld 2120 Radiator Repair Kit
The J-B Weld 2120 Radiator and Plastic Repair Kit is considered one of the best epoxy repair products for fixing cracked or leaking plastic radiator tanks. Here are the key features and benefits of this repair kit:
- Specialized Epoxy Putty – This two-part epoxy putty is specially formulated to cure into a strong, rigid material capable of withstanding high temperatures and pressures inside radiators.
- Repairs Cracks, Holes, and Leaks – The putty can repair cracks up to 4 inches long, holes up to 1/4 inch wide, and leaks in plastic radiator components.
- Withstands Automotive Fluids – The cured putty is resistant to all automotive fluids including antifreeze, coolants, brake fluids, transmission fluids, oils, and more.
- Sets in 60 Minutes – The epoxy putty sets in just 60 minutes, allowing for quick repairs. It fully cures in 6-8 hours.
- Can Be Drilled, Sanded, Machined – The rigid cured putty can be sanded, drilled, tapped, machined, or painted if needed after repairs.
With its reliability, versatility, and ease of use, the J-B Weld 2120 is a top choice for DIY repairs of cracks, holes, or leaks in plastic radiator tanks. Follow the instructions for surface preparation and application to ensure effective repairs.
J-B Weld 8237 PlasticWeld Epoxy Putty
Another excellent epoxy option for plastic radiator repair is J-B Weld 8237 PlasticWeld Putty, which offers these features:
- Multi-Purpose Plastic Epoxy – This epoxy putty is designed to bond to many types of plastic, making it suitable for radiator tanks.
- Strong and Impact Resistant – It cures into a rigid material that is highly impact resistant, helping repairs withstand pressure and temperature changes.
- Versatile Repairs – The putty can be used to repair cracks, holes, leaks, and also rebuild damaged sections or missing pieces.
- Easy Application – The putty consistency allows it to be molded and shaped as needed for repairs.
- Paintable and Sandable – Once fully cured, the putty can be sanded, machined, drilled, or painted for cosmetic repairs.
The J-B Weld 8237 epoxy putty is an excellent all-purpose option for fixing damaged plastic radiator components. It provides reliable repairs that can withstand years of service.
Permatex 84145 Radiator Repair Kit
The Permatex 84145 Radiator Repair Kit is another complete kit designed to repair plastic radiator tanks, overflow tanks, and other components. Key features include:
- Specialized Plastic Repair Epoxy – Contains a two-part epoxy putty compound formulated to bond to plastic and cure into a rigid, durable repair.
- Reinforcing Fiberglass Cloth – Includes fiberglass mesh for reinforcing and strengthening repairs on cracks or holes.
- Withstands Burst Pressures – Repairs can withstand the high internal pressures inside radiator systems.
- Easy to Apply – Putty spreads easily and molds into cracks or holes.
- Bonds When Wet – Can apply epoxy putty even if the surface is wet for quick repairs.
- Full Cure in 6 Hours – The epoxy fully cures in just 6 hours after application.
The Permatex 84145 kit provides all the materials in one package for complete radiator tank repairs. The specialized epoxy putty and fiberglass cloth result in reliable, long-term fixes.
Loctite 1363377 Epoxy Putty Stick
For a quick plastic radiator repair, the Loctite 1363377 Putty Stick offers convenient application. Features include:
- Pre-Mixed Epoxy Putty – The two-part epoxy resin and hardener are pre-mixed, so no measuring or mixing is required.
- Stick Form – The putty is a solid stick that can be cut, molded, and shaped as needed for repairs.
- Bonds to Plastic – Formulated to adhere strongly to plastics like those used in radiator tanks.
- Fast Cure – Fully cures and is sandable in just 2-3 hours.
- Hand Moldable – No tools needed – the putty can be shaped completely by hand.
The pre-mixed putty stick is useful for quick fixes or minor repairs. Simply cut the required amount of putty and mold it into holes, cracks, or leaks in the plastic radiator components.
Polyvance PR-3 Radiator Repair Kit
For professional-quality repairs, the Polyvance PR-3 Radiator Repair Kit is an excellent choice. It contains:
- Plastic Welding Tool – A specialized heat tool for fusing and welding plastic radiator tank materials.
- Plastic Welding Rods – Plastic welding rods create a strong, sealed repair.
- Surface Cleaners – Chemically cleans and prepares the surface for optimal welding.
- Sanding Pads – For smoothing the repair area.
- Detailed Instructions – Provides step-by-step repair procedures.
This kit allows for seamless, factory-quality repairs of cracks, holes, and other radiator tank damage. It takes some practice but produces reliable, long-lasting fixes. The kit works on most plastic radiator tank materials.
Step-By-Step Instructions for Epoxy Radiator Repairs
Repairing a cracked or leaking plastic radiator tank using epoxy putty involves following some important steps. Here is an overview of the complete repair process:
Gather Materials
- Epoxy putty or repair kit
- Mixing sticks/spatula
- Sandpaper
- Fiberglass mesh (optional)
- Tape (masking or duct tape)
- Gloves & safety glasses
Prepare the Surface
- Allow radiator and epoxy to reach room temperature
- Thoroughly clean repair area with soap and water
- Sand repair area with 120 grit sandpaper
- Remove any grease or oils with a degreasing agent
- Dry the surface fully
Mix and Apply Epoxy Putty
- Cut or pinch off required amount of epoxy putty
- Thoroughly knead the putty until uniform color
- Mold putty over crack or hole, pressing firmly into the gap
- Apply extra putty and smooth with a spatula
- For larger holes, add fiberglass mesh for support
Allow Proper Cure Time
- Most epoxies take 4-6 hours to fully cure
- Follow instructions for exact cure times
- Tape can hold putty in place while curing
Finish the Repair
- Once cured, sand repair smooth with 120 then 220 grit sandpaper
- Clean area and apply plastic primer and paint if needed
- Reinstall radiator and refill cooling system
- Road test vehicle to verify repair
With the proper products and application process, epoxy putty provides a relatively easy, affordable, and long-lasting repair for cracked or leaking plastic radiator components. Take care to thoroughly prepare the surface and allow adequate cure time.
Alternative Methods for Repairing Plastic Radiators
While epoxy putty repair kits are a popular DIY solution, there are some other alternative methods that can also effectively fix cracks, holes, or leaks in plastic radiator tanks.
Soldering Iron Technique
One method is using a soldering iron to melt plastic welding rods into cracks or holes. Here is the basic process:
- Clean and sand repair area
- Heat soldering iron to 700-800°F
- Melt end of plastic welding rod and drip into crack
- Repeat, layering plastic into damaged area
- Allow to fully cool and solidify
- Sand smooth
This takes some practice but can produce good repairs on small cracks and holes. Use a steady hand and work slowly.
Plastic Radiator Tank Repair Kits
There are also commercial plastic tank repair kits like the Polyvance PR-1 Plastic Repair Kit. These contain:
- A specialized heat tool to melt and fuse plastic
- Plastic welding rods to fill cracks
- Surface preparation materials
- Detailed instructions
Kits like this allow for professional-quality repairs similar to a factory weld. Larger repairs are possible with these tools.
Professional Repair Shops
For very large cracks or extensive damage, it may be best to take the radiator to a professional auto repair shop for service. They can utilize specialized plastic welding equipment to restore plastic tanks and components. This is the most reliable option but also the most costly.
For minor cracks and holes, DIY epoxy or plastic welding kits can be a very effective solution if applied properly. But for more advanced repairs, professionals may be needed.
Where to Buy Epoxy and Repair Products for Plastic Radiators
Many of the epoxy putties, adhesives, and repair kits mentioned in this article can be found at local auto parts stores:
- AutoZone – Carries J-B Weld, Loctite, and Permatex repair products. Some stores offer free shipping to your local store.
- O’Reilly Auto Parts – Sells J-B Weld epoxy putties and the Permatex repair kit for plastic radiators. Items can be ordered online.
- NAPA Auto Parts – Stocks J-B Weld and Permatex epoxy putties in many stores and online.
- Amazon – Sells all the major brands including J-B Weld, Loctite, Permatex, and Polyvance repair kits with quick shipping.
Check product listings for availability at specific local stores. Products that require mixing two parts will have the longest shelf life before use. Follow all safety instructions when using epoxy adhesives.
Final Thoughts
Proper surface cleaning and preparation is critical for successful repairs. Ensure the repair area is free of dirt, oil, coolant, or other contaminants. Lightly sanding provides the best surface for epoxy putty adhesion. Apply repairs in a well-ventilated area and allow adequate curing time before handling.
With the right materials and proper application, DIYers can successfully repair minor cracks, holes, and leaks in plastic radiator tanks and avoid the high cost of full radiator replacement. Epoxy putties and repair kits are economical and long-lasting solutions for fixing many common plastic radiator damages.