US Patent 10016856 Method of rebuilding an EGR cooler

A method of rebuilding a salvaged EGR coolers is disclosed in which the existing heat exchanger elements are removed from the salvaged stock EGR cooler housing and replaced with a heat exchanger element made from a pair of heat exchanger tube sub-assemblies. Each of the heat exchanger tube sub-assemblies includes an end plate with a selected number of attached tubes and a selected number of bores, which are adapted to receive the ends of the tubes attached to the other tube sub-assembly. The tube sub-assemblies are mated together with the free ends of the tubes received into the bores of the opposite end plate. Exhaust fittings are then welded to the ends of the housing.