Perrin Air Oil Separator for 2022-2026 WRX | PSP-ENG-622

The PERRIN Air Oil Separator replaces part of the factory crankcase-vent routing with a coolant-heated, self-draining separator. Internal swirl passages and impact surfaces pull oil from blow-by gases before they re-enter the intake, then return collected oil to the engine instead of requiring routine catch-can draining. The 2022-2026 WRX kit includes application-specific mounting hardware, aluminum fittings, and hoses, and PERRIN lists compatibility with common intercooler, charge-pipe, intake, master-cylinder-brace, and CAN Flex Fuel configurations. Installation is involved: the intercooler, charge pipe, radiator fan, PCV plumbing, and coolant hoses are disturbed, so leak checks and a coolant-level check are essential. No ECU calibration is identified for this crankcase-ventilation change.