A turbocharger compresses the air that enters the engine forcing the injection of more fuel, this boosts the horsepower and cures the problem of the car lagging at high altitude. It has a housing in which there are two turbines, one at the ends of the same axis, where the first is exposed to the hot exhaust gases and the second, known as the impeller, compress the entering air. The compressed air is heated and then ducted to a charge air cooler to cool the air and thus facilitate...combustion, enhance power output and emission. Boost levels are controlled by wastegate where at high engine revs, the boost is limited at some level by allowing exhaust gases to bypass the turbine. The turbocharger is cooled by the coolant supplied by the supply and return lines associated with the engine. Despite this, it is a rather uncomplicated device, and disassembling and overhaul should be done with special tools, so it is best to leave the servicing to the professionals while some inspections can be done at home, for example, if the examined part shows the signs of cracks or bearings wear. Any change of the acoustic note of the turbocharger therefore needs to be investigated because any strange note should be viewed as evidence of malfunction and the intake duct as well as the compressor wheel ought to be checked to ensure that it moves freely. Engine oil under pressures, filtered and cooled is supplied to the turbocharger through a supply line and the waste oil is recirculated to the crank case. Disruptions or pollution of the oil supply are dangerous, and soot on the outer walls of the housing can mean that the return line is clogged. When through major engine bearings, it important to ensure that the turbocharger oil passage is supplied with clear oil.