Abstract: An engine cooling system for field machinery such as tractors equipped with a lawnmower. A cooling system is arranged with a radiator placed in a slanting position in the upper rear part of engine within engine room and with the lower end of the radiator placed on the engine side. A cooling fan is so mounted that the cooling air induced by the radiator cooling fan passes through upward from under the radiator. The cooling fan is preferably placed downstream in the cooling air flow of the radiator, that means, above the radiator. Further it is desirable that a cooling air passage is so arranged that the cooling air which has passed through the radiator may blow out of air outlet through the vicinity of the engine, and that the outgoing air flow is so directed that hay blown up by field machinery's travels and operations be kept away from cooling air inlet, for instance, being directed forward ahead of the engine.