A fluid filter and an end cap of the fluid filter are described. The filter may be a spin on oil filter, which includes a combination dual valve element defining an integral anti-drain back valve and an integral relief valve, a retainer assembly for maintaining the combination dual valve element in position in the end cap, relative to the filter. The combination dual valve element includes an ADB sealing lip forming an anti-drain back valve portion, and an RV sealing lip forming a relief valve portion.