The utility model relates to an uncovered engine oil cooler used for a vehicle, comprising a lower plate and a heat radiation core composed of multiple overlapping chips, each of which is provided with an oil inlet and an oil outlet. A fin is arranged in the chips, a space ring is arranged between the contiguous chips, and the lower plate is welded above the chip at the top layer. The oil inlet, an intermediate oil inlet, an intermediate oil outlet and the oil outlet are equipped on the lower plate, the oil inlet and the intermediate oil inlet are connected through an oil channel, and the intermediate oil outlet and the oil outlet are connected through an oil outlet channel. The oil channel directly arranged on lower plate of the engine oil cooler of the utility model makes the oil inlet and the oil outlet are communicated, a cover plate is saved, and the structure of the product is greatly simplified. Since only one sealing surface that the oil inlet and the oil outlet are communicated with a reducer casing or an engine cylinder exists on the lower plate, the leakage rate of the product is decreased. Meanwhile, since the elements are decreased, the volume, the weight and the manufacture cost can be decreased.