The charge air cooler (or scavenge air intercooler) is located between the turbo charger and the engine scavenge air inlet manifold. The purpose of the charge air cooler is to reduce the air inlet temperature thereby increasing air density thus giving an increase in engine efficiency. Typically the charge air cooler will cool air from 200 ºC to 45 ºC with high air velocities. It is obviously important to meet the required performance but with the high air velocities, it is imperative that the construction has high integral strength. Seawater and fresh water are usually used as a cooling medium and high quality materials are needed to ensure a long serviceable life. Leaking or damaged charge air coolers can cause loss of power, increased emissions, increased fuel consumption and increased exhaust temperatures leading to excessive engine weardamage. The condition of the air cooler is therefore essential to ensure efficient performance of any turbo charged diesel engine.