Look over the welds on the inside where the tube meets the flange, mainly where there is a bolt hole is close to a tube. Mine leak in 3 spots, gaskets sealed 100% (aluminum ones, not the ones included). Working with them now on what they propose to do about it. I know how to weld them and fix it but I shouldn't have too on a $650 set of coated headers and I don't think the coating will stand up to the welding either.