Engine coolant takes away the heat produced by internal combustion. The radiator channels the heat away from the coolant in order to keep the metal parts that make up the engine from turning into a useless cracked and molten lump. Passages inside the radiator are connected to fins, which wick away heat from the coolant and send it away from the engine compartment. Hot coolant meanders its way from the engine into the labyrinth of channels and passages inside the radiator, and then returns to the engine considerably cooler through the miracle of heat transfer.
In order for this miracle to march on unabated, all the components of the cooling system must be in good working order. Hoses, gaskets, clamps, radiator, thermostat, fan or fans, water pump, radiator cap and the coolant itself must all be in top condition to keep the motor from melting. A regular check of coolant level will indicate if the system is holding its own. Check the coolant only when the engine is cold, and on a level surface by removing the radiator cap and peering inside the filler neck. Never open a cooling system when the vehicle is hot, or even warm.
If the coolant level in the radiator or overflow reservoir is below normal or if there are telltale signs of coolant leakage on the garage floor, first inspect the hoses and clamps for signs of seepage. Spongy or swollen hoses should be replaced immediately. Don't forget to inspect heater hoses as well. A leaking system cannot maintain the pressure required for coolant circulation. The engine will run hot and overheat, causing expensive internal damage. Also scrutinize the water pump for signs of leaking crusty coolant. If the hoses, clamps and water pump check out then move onto the radiator itself.
The automotive radiator is comprised of a core and surrounding tank. The core contains the coolant channels and fins that transfer heat away from the liquid and into the air. The tank surrounds the core and holds everything together, including the coolant. Older cores are often made of copper and brass. More modern cores are made from aluminum. Tanks can be made of brass, copper, aluminum, or plastic depending on manufacture. Each type of configuration presents its own repair challenges.
Inspect the finned surfaces for signs of leakage and seams of the finned surface join up with the surrounding tank. Some leaks are obvious, mimicking a bright green or orange miniscule Vesuvius, while other leaks are harder to locate, and may require removal and testing of the radiator itself to locate.
Rotten to the Core.
One crucial way to keep the radiator and entire cooling system in good shape is to change and flush the coolant according to manufacturer's recommendations. Neglected coolant becomes corrosive to the cooling system and will cause a myriad of problems. If the radiator is in good shape overall both core and tank leaks can be repaired. If, however, the corrosion has advanced to the point where the radiator has become compromised, then replacement may be the only option.
When considering radiator repair always consult an automotive cooling system specialist. It may be more cost effective to actually replace the radiator in some cases. A reputable radiator repair shop will be able to determine whether radiator repair is an option, or if replacement is the answer. Follow along with the step-by-steps to see what it takes to repair a leaking radiator the right way.