charge-air cooler This charge-air cooler is an air/water heat exchanger with a separate coolant circulation. The water and air channels have been cut away and painted accordingly. description ordernumber 1300 see also: Audi cylinder head with 5 valves two-stage twin-choke downdraught carburetor 4A1 MAN direct injection with bowl-in piston distributor-type fuel-injection pump with centrifugal governor