Abstract: A heat exchanger assembly for an automotive vehicle is provided. The assembly includes a generally rectangular heat exchanger core defining four generally orthogonal ends and a housing configured to receive the heat exchanger core therein. The housing bas a plurality of walls disposed around the ends of the heat exchanger core. At least two of the walls and at least two of the ends cooperate to define a sealing space therebetween. Each of the at least two walls has an injection port provided therein for receiving a seal precursor material into the sealing space. The assembly also includes a seal formed from the precursor material in the sealing space, the seal substantially filling the space.