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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Donna M.
Massapequa, US
★★★★★ 5
Great toy
Color: Blue
Great toy, too bad my Shih Tzu is afraid of it. I love the way the movement is subtle and random.
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Reviewed in the United States on May 21, 2026
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Amazon Customer
Grantham, US
★★★★★ 5
Best toy for dogs
Color: Blue
My dog plays with this for hours!
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Reviewed in the United States on May 14, 2026
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Chelsea H.
Phoenix, US
★★★★★ 4
I wouldn’t recommend this for strong chewers.
Color: Orange, Color: Orange
Is it fun? Sure. Was it easy to charge and set up? Yep. That being said, this toy kind of fell flat for me. It really didn’t do any big movements once charged that I expected it to, so that was a bummer. I initially got it for my dog, but my cats were more interested in this than my dog was. The battery does seem to last a long time and the motor is pretty quiet. I WOULD NOT recommend this toy for strong chewers as the material for this is a foam rubber and I don’t think it’s durable enough for strong chewers. While the material makes this ball extremely lightweight for more movement, a strong chewer would have this disintegrated in five minutes flat. My Dog is a super strong chewer. I don’t think I would feel comfortable leaving him unattended with this because I know he would destroy it.
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Reviewed in the United States on May 5, 2026
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Verified Purchase
Charlie
Houston, US
★★★★★ 5
Interactive puppy fun
Color: Blue
Pups love this and I enjoy watching them have so much fun. Serious playtime followed by a well earned nap!
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Reviewed in the United States on May 4, 2026
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Nala Nose Best 🐾
Carnegie, US
★★★★★ 3
Well-designed and quiet, but didn’t keep my dog interested
Color: Blue
My dog was interested in this at first, but she would lose interest after a few minutes and move on. I do like that it’s quieter than the hard plastic ball toys, and the charge lasts well. The internal charging port that twists closed is also a nice design feature. That said, it will occasionally turn on by itself, which can be a little surprising. Overall, it has some nice features, but it just didn’t keep my dog engaged.
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Reviewed in the United States on April 30, 2026

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