A conventional air filtration system, such as those used in over-the-road trucks and in agricultural, automotive, and off-highway equipment, is employed to prevent dirt and dust from entering the engine with the incoming air supply. These conventional air filtration systems may include, among other things, a housing, an air flow tube associated with the housing, and a removable and replaceable air filter element. Air filter elements may include an inner metal liner, an outer metal liner, a filter media, and a pair of end caps. The filter media is disposed between the metal liners. The end caps generally secure the metal liners on opposing sides of the filter element and seal all or a portion of the filter media. It is known to use metal and polymeric end caps as indicated generally by U.S. Pat. No. 6,413,289 entitled “Reverse Flow Air Filter Arrangement” and U.S. Pat. No. 5,484,466 entitled “Air Filter Element With Radial Seal Sealing Element”, the entire disclosures of which are incorporated by reference. The present invention relates to improvements in polymeric end caps.