Heat exchanger with bypass stopper, oil cooling system and method for cooling oil

A heat exchanger for cooling oil when immersed in a housing filled with a second fluid, comprising:

• at least two elongate heat exchanger members, each of which enclosing a respective first channel between spaced apart plates, each plate having an interior surface facing the first channel and an opposing exterior surface, the at least two elongate heat exchanger members having an inlet end region with a common oil inlet, an axially spaced apart outlet end region with common oil outlet, and an elongate central region between the inlet and outlet end regions wherein;
• a generally planar portion of the exterior surface of a first one of the heat exchanger members is facing a generally planar portion of the exterior surface of a second adjacent heat exchanger member, wherein an axially elongated second channel is formed between adjacent heat exchanger members for receiving the second fluid;
• a plurality of elongated bypass restrictors each integrally formed by an elongate edge portion of one of spaced apart plates of the heat exchanger members, extending towards an edge portion of an adjacent heat exchanger member to further define the axially elongated second channel extending along the elongate central region in an enclosed manor with the second channel opening into the housing in the inlet and outlet end regions of the elongate heat exchanger members beyond the elongated bypass restrictors, and
• the bypass restrictors forming a pair of outer walls of the heat exchanger, extending substantially in parallel with a main flow direction in the enclosed central region of the elongate second channel.