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Radium Air Oil Separator Kit 2015+ Subaru WRX STI

Radium Air Oil Separator Kit | 2015+ Subaru WRX STI (20-0207-08)

Regular price $449.95 USD $427.45 USD

Manufacturer: Radium

SKU: rad20-0207-08


The Subaru EJ25 engine has a high tendency to generate excessive blow-by oil and gasses which circulate oil into the intake system and can result in the dreaded "ringland" failure. To prevent this problem catch can systems in the CCV/PCV system work great but require a lot of maintenance.

Like the Radium Engineering Subaru Dual Catch Can Kit, the AOS (Air Oil Separator) kit is responsible for keeping blow-by oil and other pollutants out of the intake pipe, manifold, turbocharger, and intercooler during all engine loads. The main difference is that an AOS system returns what is collected back into the oil pan so there is no regular servicing required.

The built-in heater keeps water from condensing in the AOS. And because water is more dense than oil, there is an integrated water trap found around the bottom perimeter of the can. This prevents water from descending into the oil pan if ever present. Furthermore, because the water is trapped against the heater, it will eventually boil and evaporate out of the system. Ergo the "Air Oil Separator" nomenclature.

Mount works with Left-Hand Drive vehicles only

Vehicle Applications:
  • Subaru WRX STI [VAB] (2015, 2016, 2017, 2018, 2019)
  • Subaru Impreza WRX STI [GRB/GVB] (2008, 2009, 2010, 2011, 2012, 2013, 2014)
  • Subaru Impreza WRX [GR8/GV8/GH8/GE8] (2008, 2009, 2010, 2011, 2012, 2013, 2014)


Designed to safeguard your motor from engine oil in the intake system
Connects to OE lines to prevent oil in the intake system
Unlike catch can kits this automatically returns oil back into the oil pan
CNC Billet Aluminum for nice appearance
Includes firewall mounted bracket
Highly recommended for builds pushing high power

Extended Information

Type: Air Oil Seperator
Material: Billet Aluminum
Finish: Anodized Black
Engine: EJ25
Chassis: VAB / GRB / GVB
Included Parts: air oil separator body, mounting bracket, all necessary SAE J30R7 rated PCV/Emissions hoses, coolant hoses and fittings, all necessary aluminum fittings and hose-ends, and stainless steel mounting hardware

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Returns Policy

Most items may be returned within 30 days of the product arriving to your house or place of work.
Returns will NOT be accepted on special order, opened, installed, incomplete, or otherwise used products.

In order to initiate a return, an RMA number must be requested and approved. All returns will be subject to a 15% restocking fee minus complete shipping cost.
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