Radium Engineering

Radium Engineering 2015+ Subaru WRX Air Oil Separator Kit

  • Sale
  • $474.95
  • Regular price $499.95
  • 2 available

Product SKU: RAD 20-0258-00

High-powered modified Subaru engines tend to generate excessive blow-by oil and gasses. In these cases, an ordinary small catch can may quickly fill with oil and not be adequate. 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 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.

The AOS is constructed of CNC machined sections that screw together and are sealed with O-rings. The AOS can be completely disassembled for cleaning or servicing.


  • Effectively raises the fuel octane and increases engine performance with cleaner inlet air
  • Prevents oil buildup in the intake or intercooler system walls, throttle body, intake manifold, etc.
  • Lowers hydrocarbon emissions

Package Includes:

  • Specially designed mounting bracket
  • All necessary SAE J30R7 rated PCV/Emissions hose
  • Coolant hoses and fittings
  • PCV delete fitting
  • All necessary aluminum fittings and hose-ends
  • Stainless steel mounting hardware
  • Master Cylinder Brace (required to complete kit and included in 20-0258-00)

Note: Only purchase the kit without the cylinder brace if you have purcahsed 20-0255 separately. It is required for installation.

Installation instructions located at www.radiumauto.com