On vehicle and industrial engines, a CAC (charge air cooler) is normally mounted ahead of the cooling system radiator. On keel-cooled marine engines the charge air cooler is incorporated into the keel cooler tank. On heat exchanger-cooled engines, the charge air cooler is part of the intake manifold. The compressed air leaving the turbocharger is directed through the CAC before it goes to the air inlet side of the intake manifold.
The CAC is used to reduce the temperature of the compressed air leaving the turbocharger before it reaches the intake manifold. This permits a more dense charge of air to be delivered to the engine.