Abstract: An apparatus for connecting a coolant tube (20) and header (22, 24) of a heat exchanger (10) comprises manifolds (12, 14) forming fluid reservoirs (16, 18) and a plurality of coolant tubes (20) in fluid communication with the manifolds (12, 14) . The manifolds (12, 14) comprise a header wall (22, 24) having a plurality of collars (26) forming collar openings (28). The tubes (20) include an axially extending mechanical seam (50) and deformable hollow end portions (52) extending through the collar openings (28). A flaring tool (70) having tapered side surfaces (74) is inserted in the end portion (52) of the tube (20) to expand the tube (20) outwardly against the collar opening (28). The flaring tool (70) includes a groove extending axially along the side surface (74) aligning with and straddling the seam (50) during expansion of the tube (20) and further forces the portions (62, 64) of the tube (20) adjacent the seam (50) outwardly into sealing engagement with the collar opening (28).

Abstract: A method for connecting a coolant tube (20) and header (22, 24) of a heat exchanger (10) comprises manifolds (12, 14) forming fluid reservoirs (16, 18) and a plurality of coolant tubes (20) in fluid communication with the manifolds (12, 14). The manifolds (12, 14) comprise a header wall (22, 24) having a plurality of collars (26) forming collar openings (28). The tubes (20) include an axially extending mechanical seam (50) and deformable hollow end portions (52) extending through the collar openings (28). A flaring tool (70) having tapered side surfaces (74) is inserted in the end portion (52) of the tube (20) to expand the tube (20) outwardly against the collar opening (28). The flaring tool (70) includes a groove extending axially along the side surface (74) aligning with and straddling the seam (50) during expansion of the tube (20) and further forces the portions (62, 64 ) of the tube (20) adjacent the seam (50) outwardly into sealing engagement with the collar opening (28).