A plate package made according to the method includes first heat exchanger plates and second heat exchanger plates. Each heat exchanger plate has a first porthole, and the port hole of at least one of the heat exchanger plates is surrounded by a peripheral rim. The first heat exchanger plates and the second heat exchanger plates, are joined to each other and arranged side by side in such a way that the peripheral rims together define an inlet channel extending through the plate package. The peripheral rim of the first and/or the second heat exchanger plates has at least one through hole, forming a fluid passage allowing a communication between the inlet channel and the first plate interspaces. The at least one through hole is made in a condition in which the first and the second heat exchanger plates have been joined to each other to form the plate package.