The oil pump is quite literally the heart of any engine. Responsible for pumping the oil through the entire engine, it is one of the most critical parts, but often one of the most overlooked. Over the years, our experience has shown that even brand new OEM pumps direct from Subaru can be affected by inconsistencies in the assembly. In an effort to address the concerns of commonly flawed Subaru pumps, the IAG Stage 1 Blueprinted EJ25 11mm Oil Pump improves upon the factory pump by making key improvements for better overall performance.