Yes, the J-B Weld 2120 RadiatorWeld Plastic Tank/Radiator Repair Kit should be suitable for repairing a crack around the top of your radiator. This kit is designed to fix cracks up to 4 inches in length and holes up to 3/8 inches in diameter12. It includes epoxy putty, fiberglass cloth, sandpaper, and an applicator, making it a comprehensive solution for such repairs12. Here are some steps to use the kit effectively: Clean the Area: Ensure the area around the crack is clean and dry. Use sandpaper to roughen the surface for better adhesion. Mix the Epoxy Putty: Follow the instructions to mix the epoxy putty until it reaches a uniform color. Apply the Putty: Press the putty into the crack, ensuring it fills the entire area. Reinforce with Fiberglass Cloth: Place the fiberglass cloth over the putty and smooth it out. Allow to Cure: Let the repair cure as per the instructions before using the radiator. This repair kit is versatile and dependable, making it a good choice for your radiator