A transversely disposed water cooled internal combustion engine for a motor vehicle that cooperates with a heat exchanger that is disposed transversely to the engine compartment and in parallel relationship with the engine. A cooling pump and thermostat assembly is mounted on the side of the engine between its ends and facing the heat exchanger for communicating the heat exchanger with the engine cooling jacket. Coolant is delivered first to the cylinder head and then through the cylinder head to the cylinder block cooling jacket. The coolant pump is driven off to an intermediate shaft driven by the timing mechanism for driving the camshafts of the engine.