IAG AIR / Oil Separator (AOS) - 2022-2024 Subaru WRX (VB)

The Ultimate Engine Defense for the Direct-Injected FA24
On turbocharged engines like the 2.4L FA24 in the 2022-2024 WRX, aggressive driving forces oil mist and crankcase vapors back into the intake tract. Once inside, this oil coats the interior of your intercooler (drastically reducing its cooling efficiency) and enters the combustion chambers where it dilutes your fuel. Because oil has a much lower octane rating than gasoline, this oil-and-fuel mix leads to harmful engine knock and detonation. The IAG V3 Air Oil Separator (AOS) is engineered specifically to eliminate oil in your intake system, protecting your engine and preserving peak performance.

Swirl-Pot Separation with Integrated Thermal Heating
Unlike basic catch cans that rely on simple baffles and require constant manual emptying, the IAG V3 AOS uses a high-volume cast aluminum housing with a multi-stage swirl pot layout. Centrifugal force spins oil out of the crankcase gases, allowing clean air to return to the intake while automatically draining separated oil back into the oil pan. To prevent cold-weather moisture buildup and the dreaded "milky sludge," IAG integrates engine coolant passages directly into the base of the housing. This keeps the AOS at engine operating temperature, completely eliminating condensation and freezing risks.

• Stop Oil Contamination in Intake & Intercooler: Keep oil mist out of your intake, keeping intercooler cores clean and operating at maximum thermal efficiency.
• Prevent Engine Knock & Detonation: Stop crankcase oil vapors from entering the combustion chamber where they lower effective fuel octane and trigger knock retard.
• Heated Housing Technology: Taps into your factory cooling system to keep the AOS warm, preventing water condensation, sludge buildup, and freezing in cold climates.
• Maintenance-Free Drain-Back System: Automatically returns captured oil directly to the oil pan. No messy catch cans to manually drain at every gas fill-up.
• Plug-and-Play FA24 Fitment: Features vehicle-specific mounting brackets, custom-molded hoses, and quick-connect fittings designed exclusively for the 2022-2024 VB WRX engine bay.

Technical Specifications:

• Product Type: Air Oil Separator (AOS)
• Housing Material: Heavy-Duty Cast Aluminum
• Separation Method: Multi-Stage Swirl Pot & Baffling
• Thermal Control: Integrated Coolant Passage (Heated Base)
• Drain-Back Style: Automatic Gravity Drain to Engine Oil Pan
• Hose Construction: Custom Molded SAE-Rated PCV & Breather Hoses
• Engine Compatibility: 2.4L Turbo FA24F Direct-Injection Boxer
• Maintenance Requirement: Zero (Self-Draining System)

Fitment:

• Subaru WRX (VB Chassis): 2022, 2023, 2024 (2.4L Turbo FA24F Direct Injection)
  • Compatible with all trim levels: Base, Premium, Limited, Sport, Sport-tech, TR, tS, and Series.Yellow models.

Note: This does NOT fit the 2025 or 2026 WRX, but IAG is working on a version for the 2025+ WRX.

The Nameless "Installation" Pro-Tips:

Coolant Bleeding & Hose Slope Are Everything:

1. Ensure Constant Downward Slope: When routing the bottom oil drain hose back down to the engine block, verify that the line maintains a smooth, continuous downward angle with zero dips or horizontal sags. Any "U" shape in the drain line will create a liquid trap, preventing oil from returning to the pan and causing the separator to back up.

2. Burp the Cooling System: Because this kit taps into your factory heater core lines to warm the AOS body, you will introduce air pockets into the cooling system during install. Always fill and thoroughly burp your cooling system using a no-spill coolant funnel after installation. Trapped air in the FA24 cooling system can cause erratic idle temps or improper heater core operation!