The housing of the heat exchanger has an elongated body section. Located within the body section are two axially-spaced radiallydisposed header plates with a plurality of axial apertures. Extending through the apertures are a plurality of elongated tubes. The body section and the header plates are compressed radially inwardly to effect a tight engagement between the body section and the header plates and between the header plates and the tubes. Brazing material seals the header plates to the body section and seals the tubes to the header plates.