Engines generate a great deal of heat while creating the energy to move your car forward. To offset this, engines are cooled by a radiator that dissipates heat that could otherwise damage or ruin the engine.
How Radiators Work
A radiator holds fluid designed to cool your engine by running through cylinders in your engine and flowing back into the radiator where it dissipates the heat. An overheated engine can cause a piston to snap or the cap--called the head--of a piston cylinder to break, which ruins an engine. A water pump keeps the coolant and water mixture in your radiator moving throughout the car's engine and back into the radiator. The heat is dissipated in the radiator by a fan and by the air flowing over the radiator as the car moves.
It is important to check the coolant level of your radiator periodically to make sure the coolant is at a proper level to keep the engine cool. Antifreeze should be added to the coolant before cold weather arrives to prevent the radiator from freezing and cracking. If a radiator develops a crack, coolant leaks out and your car could become overheated quickly.
Often you can fix a radiator temporarily to keep your car operational until you can get it to a mechanic. Depending on the location of the leak, you may be able to patch it until a professional can provide a permanent solution. A hose that leaks is simple to replace, and the use of a cold weld epoxy such as J-B Weld can seal a leak in the radiator itself, according to the Radiator website. That website also states radiator sealant may clog the radiator and may not plug the leak sufficiently.