SKU: 14371857191

Radium Engineering Air Oil Separator AOS-R – 2015-2020 Subaru WRX STi

Sale price$189.45 Regular price$210.50
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Description

Radium Engineering Air Oil Separator AOS-R – 2015-2020 Subaru WRX STiHigh 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 R

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-“R” 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 three CNC machined sections that screw together and are sealed with O-rings.

Measurements
AOS Height: 6.94″ (top of the dipstick to bottom of AOS)
AOS Diameter: 3.45″ Round
AOS Capacity: 20.3 oz (600mL)


Benefits
-Effectively raises the 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


Included
-Machined aluminum Radium Engineering Air Oil Separator
-Specially designed mounting bracket (see note at bottom of page)
-All necessary SAE J30R7 rated PCV/Emissions hose
-Coolant hoses and fittings
-All necessary aluminum fittings and hose-ends
-Stainless steel mounting hardware

NOTES

*If operated in freezing environments, Radium Engineering recommends installing insulation sleeving (not included) over any hose exposed to cold airflow. This will help prevent the natural phenomenon of water condensation freezing and potentially clogging the hose.

*For RHD vehicles, our Universal AOS-R must be used for custom mounting and plumbing.

*The Radium AOS-R kit may not be compatible with all other aftermarket products. 

Shipping Notes
  • Free Standard Shipping on $100+ Orders to the USA.
  • Except Preorder products are shipped in 48 hours.
  • Delivery to the USA:
  1. Standard Shipping : 3-10 business days
  • If time is of the essence, please consider selecting expedited delivery for faster service.
Exchange/Return Notes
  • We offer a 30-day return/exchange service after receiving.
  • Final sale items are not eligible for returns or exchanges.
  • To process your return/exchange, please contact us at [email protected]
  • Please click here for more details>>> Return & Exchange Policy
SKU: 14371857191

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KelQL
Lexington, US
★★★★★ 5
Cute slip-ons - so easy and quick!
Size: 13 Little Kid, Color: Hot Pink/Multi
These shoes are adorable, comfortable according to my kid, and super easy to pull on!
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Reviewed in the United States on January 17, 2026
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Rick
Belleville, US
★★★★★ 5
Durable
Size: 6 Big Kid, Color: Aqua/Multi
Good shoes. True to size
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Reviewed in the United States on February 18, 2026
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Redhead75
West Palm Beach, US
★★★★★ 5
So good!
Size: 4 Big Kid, Color: Aqua/Multi
As always sketchers give her great support nd comfort while being cute and easy on off! Slip resistant, breathable and size is spot on and super durable wash great and dry quick
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Reviewed in the United States on October 28, 2025
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AMA
Pawtucket, US
★★★★★ 5
Fantastic, stylish, and easy shoes!
Size: 2.5 Little Kid, Color: Aqua/Multi
My daughter LOVES these and wears them daily. She says they're really comfy and they slip on easily. They've held up for several months of daily wear so far and are still going strong!
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Reviewed in the United States on September 15, 2025
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Janis H.
New York, US
★★★★★ 5
Great shoes
Size: 3.5 Big Kid, Color: Hot Pink/Multi
These shoes are awesome! Have good arch support and very comfortable
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Reviewed in the United States on May 12, 2026

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