When your radiator is cracked, all is not lost. There are repairs you can do yourself that will seal the crack and allow you to continue to use the radiator. However, the crack will need to be small enough so you can bridge the gap. If the crack grows into a large hole, it may be necessary to replace the radiator.


To repair the crack, you must remove the radiator. First, drain any fluids from it. Then, disconnect the hoses and carefully remove the radiator without damaging any of the fins. 

Epoxy hardeners used for plastics can be an effective tool in sealing a crack. Soldering the crack is another option. Before using either method, you will need to make sure that the area is cleaned thoroughly so that the solder or epoxy will easily adhere to the radiator. Use a steel wire brush to remove any paint. While cleaning, be careful not to damage the radiator and increase the size of the hole.

Epoxy Repair

Using the epoxy method, the goal is to suck the epoxy into the crack using a vacuum hose. Move the overflow line to the vacuum port. Remove the distributor cap and turn the motor on. This will create a suction that will pull the epoxy into the radiator.


If you will solder, use a high wattage soldering iron and heavy wire. The soldering iron should be held to the radiator until it is hot enough to accept the solder and wire readily. Then, solder the wire into the radiator. Apply the solder completely over the crack until there is no opening. If any opening is left behind, the crack will be morel likely to widen again, requiring further repairs.

Finishing The Repairs

After you have performed the necessary repairs, grind the radiator to give it a flat finish. This can be accomplished by using a steel brush to remove the sharp edges that remain after the radiator has been repaired. Once you have achieved a flat, smooth finish, the radiator will be less likely to leak.

Leak Prevention Additives

There are special additives that can be added to a radiator that are designed to stop leaks. You will usually want to have your system flushed before you use the additive. These techniques are often effective, but if you are still not able to repair the leak, it is time to visit a transmission repair technician like those found at Branford Radiator Repair Service.