Abstract: A multi-engine plant with a common freshwater cooling system comprises turbocharged diesel engines (1) which in their coolant system are provided with a charging air cooler 911), a high-temperature circuit (HT) and a low-temperature circuit (LT). The high-temperature circuit (4) contains a fist three-way circuit delivery pipe (7) to the engine with coolant. The low-temperature circuit (5) contains a second three-way valve (13) supplying coolant to the delivery pipe (14) of the charging air cooler in the LT circuit. The charging air cooler (11) is a two-step cooler in which the first step (10) is part of the HT circuit and the second step (19) is part o the LT circuit. A control valve (16) can adjust the coolant flow through the second step in dependency of the engine load. The discharge pipe (15) from the control valve is connected to the second three-way valve and a common return pipe (3).