Abstract: A fixture is provided for retaining radiators for repair and/or replacement of radiator tanks and/or cores. A frame is provided with a pair of jaws, one of the jaws being movable manually and by means of a driving element to secure a radiator between the jaws. Guideways are provided in the frame for a crimping tool which is slidable along the guideways to effect crimping of the tabs to secure the radiator header to the tank. A pivotable assembly is disposed above the jaws with air cylinders and pistons for retaining the radiator tank in engagement with the core.