a permanent magnet array iron filter has a generally circular collar made of a high magnetic permeability material with a plurality of magnetic assemblies interiorly disposed longitudinally around an interior circumference therein . each magnetic assembly has two magnets with opposite poles facing the center of the filter and a gap between the adjacent assemblies . this arrangement intensifies the resultant magnetic field and projects the field deeply within the interior region of the filter . rare earth permanent magnets are used to maximize the magnetic field . the collar may be coated with a plastic coating to protect the filter . the collar has a gap to provide flexibility when sliding the filter over an oil filter . the thickness of the collar may be adjusted to meet the requirements of a particular application .