AC Delco Oil Filter is engineered to meet all the high standards set by the industry. It helps capture harmful contaminants that can harm the engine， thereby helping to increase the lifespan of the engine. This unit is put through a variety of tests under extreme and unusual conditions to ensure high quality and dependability. The PF48E primary performance improvement relates to the relief valve design. The PF48E has a compression spring loaded nylon poppet that outperforms the current valve design.