End cap relief valve mechanism for a filter

An oil filter comprises a housing that is open at one end and has an end plate connected to the housing for closing the open end. The end plate has at least one inlet opening and an outlet opening therein. An anti-drain back valve is provided for precluding return flow of oil through the inlet opening. An annular filter media is disposed in said housing. An end cap is provided at each end of the filter media. The end cap remote from the end plate has at least one opening spaced radially outwardly from the central axis thereof. A spring cooperates with said end cap remote from the end plate. Normally, the opening in the spring is closed to oil flow. When the filter media becomes clogged, the pressure within the housing increases and when the pressure differential across the end cap remote from the end plate exceeds a predetermined value, the opening in the spring is opened for oil flow. The anti-drain back valve is disposed between the end cap adjacent the end plate and the end plate and the spring is constructed and arranged to engage the interior of the housing so as to load the filter media and the end cap adjacent to the end plate to help retain the anti-drain back valve in place. A seal is provided between the end cap remote from the end plate and the spring. The spring and the end plate remote from the end plate are constructed and arranged to operationally interengage and provide a relatively flat profile.