An intercooler is a key component on most cars with a forced induction system, the radiator is a key component of every vehicle. They serve very different purposes, though they function in a similar way and look similar.
The radiator is a liquid-to-air heat exchanger, while the intercooler is a air-to-air heat exchanger. A radiator keeps the engines coolant at the correct temperature, while the intercooler cools down the compressed intake air.
The intercooler is used to cool compressed air from the forced induction system, increasing oxygen density.
The radiator cools the coolant, keeping it at its optimum operating temperature.
Intercoolers are usually an air-to-air heat exchanger, though liquid-to-air intercoolers do exist, typically on expensive cars.
Radiators are a water-to-air heat exchanger.
Intercoolers are exclusively found on forced induction vehicles (turbocharged, supercharged, etc).
Radiators are found on every vehicle.
A radiator distributes heat from your cars coolant to the atmosphere by pumping coolant through a heat exchanger. If your radiator has a fan, it can suck air through your radiator to help cool it down, this can happen while the car is stationary or after the engine shuts off.
Engines emit a lot of heat when they're running. Your vehicle's cooling system pumps coolant through the engine, the coolant absorbs the heat from the engine and transports it away from the block.
Coolant transports heat generated by your engine to the radiator, which cools it by ambient air flowing through the radiator and exchanging the heat with the atmosphere. Radiators made of aluminium or copper are used in many contemporary automobiles.
The quantity of heat transmitted from the coolant running through these tubes is determined by the temperature differential between the coolant and ambient air temperature. As a result, if the coolant's temperature drops rapidly, less heat is transferred.
An intercooler is a component that lowers the temperature of the intake air in forced induction vehicles. It works in the same way as a radiator by exchanging heat from the intake air to the ambient air.
The difference between the two is that an intercooler is an air-to-air heat exchanger while the radiator is an air-to-water heat exchanger.
The turbocharger or supercharger works by compressing air and increasing its density before it reaches the cylinders of your engine. This process generates a lot of heat, which raises the temperature of the air entering the engine.
However, when the temperature of the air rises, it gets less dense, reducing the oxygen concentration of the individual cylinders. All of this reduces the efficiency of your engine. Cooling the compressed air increases its oxygen density and therefore power and efficiency.
Because water is a much better heat conductor than air, air-to-water intercoolers are ideal for engines with limited space or very high power output. Additionally, because water is a much better heat conductor than air, this intercooler is optimal for a broad range of temperatures.
Because of this fact, air-to-air intercoolers are often placed in front of the radiator to improve their effectiveness.