Liquid cooled multi cylinder internal combustion engine and method to operate such an engine

The engine has an exhaust manifold (10a) including an outer separating wall fluidly dividing exhaust lines (6). A coolant jacket includes a lower coolant jacket (16a) arranged among exhaust lines and an exterior side-wall (8) of a cylinder head (1). An upper coolant jacket (16b) is arranged on a side of the exhaust lines opposite to the lower coolant jacket, where a connection portion (13) is provided between the lower and upper coolant jackets that serve for passing coolant, and the connection portion is arranged in close proximity to a merged exhaust pipe.