Radiators are used for cooling internal combustion engines, chiefly in automobiles but also in piston-engined aircraft, railway locomotives, motorcycles, stationary generating plant or any similar use of such an engine.

They operate by passing a liquid coolant through the engine block, where it is heated, then through the radiator itself where it loses this heat to the atmosphere. This coolant is usually water-based, but may also be oil. It's usual for the coolant flow to be pumped, also for a fan to blow air through the radiator.

Radiator construction

Automobile radiators are constructed of a pair of header tanks, linked by a core with many narrow passageways, thus a high surface area relative to its volume. This core is usually made of stacked layers of metal sheet, pressed to form channels and soldered or brazed together. For many years radiators were made from brass or copper cores soldered to brass headers. Modern radiators save money and weight by using plastic headers and may use aluminium cores. This construction is less easily repaired than traditional materials.