RADIUM ENGINEERING 20-0258-00 Aos Air Oil Separator Kit

( Brand: Radium Engineering ), ( Part Type: Oil ), ( Universal Fitment: No ), ( Performance Part: Yes ), ( Manufacturer Warranty: 1 Year ), ( California Prop 65 Warning: Applies ), ( Manufacturer Part Number: 20-0258-00 ), ( Material: Metal )

Review RADIUM ENGINEERING Aos Air Oil Separator Kit Subaru fits FORESTER XT 2014–2018

The Radium Engineering AOS (Air-Oil Separator) Kit part number 20-0258-00 is a must-have upgrade for Subaru Forester XT owners from the model years 2014 to 2018. This high-performance separator kit is designed to improve the functionality and efficiency of the factory AOS system, ensuring optimal engine performance and longevity.

The heart of this kit is a robust, CNC-machined billet aluminum separator housing. This superior design offers superior flow rates, increased capacity, and unmatched durability compared to the OEM plastic housing. The baffled design of the housing effectively separates the oil droplets from the compressor discharge air, reducing the amount of oil carryover that can lead to crankcase contamination and potential engine damage.

The kit includes a high-performance, pleated paper filter, which boasts a larger filtration area and greater efficiency than the OEM filter. This filter effectively traps the smaller oil droplets and larger particles, ensuring cleaner air enters the intercooler, resulting in improved cooling performance and increased engine durability.

Radium Engineering's 20-0258-00 AOS Kit also features an integrated, high-flow, -6AN oil return line, which is a significant upgrade from the OEM -4AN line. This larger line diameter ensures that the oil is returned to the engine more efficiently, reducing the load on the oil pump and promoting consistent oil pressure throughout the system.

Furthermore, the kit comes with a revised crankcase vent hose, engineered to minimize turbulence and provide a smoother flow of crankcase gases. This, in turn, leads to improved sealing and a reduction in crankcase pressure, which can help prevent oil foaming and potential engine damage.

Installation of the Radium Engineering AOS Kit is straightforward and can be completed using standard hand tools. The kit includes all necessary hardware, gaskets, and detailed instructions to make the installation process as hassle-free as possible.

Upgrading your Subaru Forester XT with the Radium Engineering 20-0258-00 AOS Kit is an investment in your vehicle's performance and long-term health. By improving the air-oil separation process, you'll enjoy increased engine efficiency, improved cooling performance, and extended engine life.

Radium Engineering AOS (Air-Oil Separator) Kit (20-0258-00) for 2014-2018 Subaru Forester XT: Pros and Cons

The Radium Engineering AOS kit is designed to improve the performance and longevity of the engine in Subaru Forester XT models by separating oil mist from the crankcase vent gases before they enter the intake system. Below are some potential advantages and disadvantages of this product.

1. Enhances Engine Performance: By separating oil mist from the intake gases, the AOS kit ensures that clean air enters the engine, allowing it to run more efficiently and effectively.

2. Reduces Engine Wear: The oil mist, when ingested into the engine, can cause wear and tear on the valves, piston rings, and other components. The AOS kit prevents this oil mist from reaching the intake system, thereby reducing the risk of engine wear.

3. Improves Engine Longevity: By protecting the engine from oil mist and other contaminants, the AOS kit can help improve the overall longevity of the engine.

4. Easy Installation: The kit comes with all necessary components and instructions for installation, making it a relatively straightforward process for most DIY enthusiasts.

5. Durable Construction: The Radium Engineering AOS kit is made of high-quality materials and is designed to withstand the rigors of frequent use.

1. Cost: The Radium Engineering AOS kit is more expensive than some other aftermarket options.

2. Size: Due to its size and design, installing the kit may require some modification to the engine bay or the use of additional brackets.

3. Maintenance: The AOS kit requires regular maintenance, including periodic draining and cleaning, to ensure optimal performance.

The Radium Engineering AOS kit for the 2014-2018 Subaru Forester XT offers several advantages, including improved engine performance, reduced wear, and enhanced longevity. However, it comes with some drawbacks, such as cost, size, and maintenance requirements. Ultimately, the decision to purchase this kit depends on the individual's priorities, budget, and technical skills.

If you are a performance enthusiast or someone who values the longevity of their engine, the Radium Engineering AOS kit is a worthwhile investment. However, if you are on a tight budget or prefer a more straightforward installation process, there may be other, less expensive options available. It's essential to weigh the pros and cons carefully before making a decision.

Details:

Stainless steel hardware. Lowers hydrocarbon emissions. Effectively raises the octane and increases engine performance with cleaner inlet air. Application: 2014 2018 Subaru Forester XT.

The AOS must be mounted high enough in the engin so that port on bottom is higher than oil return. Conversely, the entire billet unit disassembles into 3 large pieces for servicing. Two 5/16 barbed fittings for coolant lines. Engine coolant must be available to routed AOS in order facilitate heating it so that functions correctly.

Machined aluminum Radium Engineering AOS. If there is a possible return obstruction, simply unscrew the anodized billet aluminum dipstick for inspection. For AOS crankcase plumbing, the valve cover vent are routed into top inlet where stainless steel condensing material separates oil from gasses. Prevents oil buildup in the intake or inter cooler system walls, throttle body, manifold, etc.

Anodized universal mount that permits 360deg rotation. In order for the AOS to function properly, a port must be supplied on engine oil return through. The filtered liquid oil is collected at the bottom of AOS and drawn into pan. Meanwhile, the clean crankcase air can either be vented to atmosphere VTA or recirculated turbo inlet pipe.

Engine coolant lines are routed through the Radium Engineering AOS in a specially designed heating chamber. Without a properly designed AOS, water condensation can develop and find its way in the oil pan contaminating engine. In these cases, an ordinary small catch can may quickly fill with oil and not be adequate.

This keeps the AOS warm and prevents water from condensing inside.

part #: 20025800 prices

• $474.95-$488.95

specifications lowerlageen:

• for models: Xt, Forester
• for makes: Subaru
• for years: 2014-2018
• brand: Radium Engineering
• part type: Oil
• universal fitment: No
• performance part: Yes
• manufacturer warranty: 1 Year
• california prop 65 warning: Applies
• manufacturer part number: 20-0258-00
• material: Metal

offer lowerlageen:

• quantity: 2
• availability: In Stock
• sold: 0
• options: Ship-to-home
• started: October 8, 2025

shipping lowerlageen:

• cost: $0.00
• service: UPS Ground, UPS 3 Day Select
• transit: 3-9 Days
• type: Fixed
• carrier: UPS
• class: Standard, Expedited

returns lowerlageen:

• time: 30 Days
• policy: Returns Accepted
• paid by: Seller

seller lowerlageen:

• city: Baldwin Park, California
• rating: 99.1%
• # reviews: 19184

general lowerlageen:

• Car Truck Parts Accessories > Engines Engine Parts > Other Engine Parts
• condition: New

payments lowerlageen:

• wallet: Google-pay
• credit card: Discover
• other

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