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.