A strong air oil separator captures oil-laden crankcase vapors before they can contaminate the intake, and the right choice depends first on your vehicle and ventilation layout. This roundup compares seven options, from vehicle-specific K&N catch cans for Ford and GM trucks to IAG Performance’s Subaru AOS and a universal EVIL ENERGY kit. The products are not interchangeable: several are designed around particular model years or engines, while the universal kit requires you to check hose diameter, fittings and mounting room.
We rank specific-fit options ahead of general-purpose hardware and distinguish a complete assembly from a catch can. Confirm the exact vehicle application and whether the product suits your PCV or CCV routing before ordering; listed fitment is not a substitute for checking your vehicle configuration.
The K&N Air Oil Separator 81-0800 is the leading pick for its stated fit across 2011–2023 Ford F-150 models and 2017–2023 F-150 Raptor. Its six-ounce reservoir is intended to capture blowby oil, and the listing describes factory-style hose connections and installation in about 30 minutes. It leads this selection for buyers whose truck matches that application; it is not a universal choice, so verify engine and model compatibility before purchase.
Our Top Picks
Best OverallIts stated fit covers 2011–2023 F-150 and 2017–2023 Raptor, with a six-ounce reservoir and factory-style hose connections.
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Newer GM TrucksThis K&N option targets 2019–2023 Silverado and Sierra 1500 plus newer Suburban, Tahoe and Yukon applications, with a six-ounce reservoir.
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Earlier GM TrucksIts listed applications include 2014–2018 Silverado and Sierra 1500 and 2015–2020 Suburban and Tahoe; the reservoir holds six ounces.
View on Amazon- Subaru AOS IAG Performance Subaru AOS
- F-150 Fitment Range EVIL ENERGY F-150 Catch Can
Compare Air Oil Separators by Vehicle Fit and Design
| # | Product | Weight | Buy |
|---|---|---|---|
| 1 | 1. K&N 81-0800 SeparatorBest Overall | 2.5 lb | View on Amazon |
| 2 | 2. K&N 81-0804 SeparatorNewer GM Trucks | 1.83 lb | View on Amazon |
| 3 | 3. K&N 81-0805 SeparatorEarlier GM Trucks | 2 lb | View on Amazon |
| 4 |  4. IAG Performance Subaru AOSSubaru AOS | 10.5 lb | View on Amazon |
| 5 |  5. EVIL ENERGY F-150 Catch CanF-150 Fitment Range | 2.27 lb | View on Amazon |
| 6 |  6. RHAOCZIYAUTO CCV AssemblySuper Duty diesel replacement buyers | 1.56 lb | View on Amazon |
| 7 |  7. EVIL ENERGY 300ml Catch CanUniversal-kit setup planners | 0.91 kg | View on Amazon |
Detailed Reviews: Best Air Oil Separator
#1 · Best Overall
1. K&N 81-0800 Separator
- Weight: 2.5 lb
Best for: Ford F-150 and Raptor owners.
Why it ranks #1: Its stated fit covers 2011–2023 F-150 and 2017–2023 Raptor, with a six-ounce reservoir and factory-style hose connections.
K&N’s 6-ounce reservoir captures blowby oil for listed 2011–2023 Ford F-150 and 2017–2023 F-150 Raptor applications. That capacity supports oil capture before it reaches the engine and intake tract, while factory-style hose connections and an approximately 30-minute installation estimate give buyers useful expectations for the fitting workflow.
This vehicle-specific separator targets blowby protection on the listed F-150 and Raptor model years, aiming to limit oil and contaminant buildup in the intake manifold and intake tract. The 6-ounce reservoir captures the oil, while factory-style hose connections are described as snapping on and off for a simpler connection process. K&N estimates installation at about 30 minutes with basic tools; the supplied application range remains the key compatibility check.
- 6-ounce high-capacity reservoir captures blowby oil
- Lists Ford F-150 model years 2011–2023
- Lists F-150 Raptor model years 2017–2023
- Factory-style hose connections and about 30-minute installation estimate
- Fitment is limited to the listed Ford F-150 and Raptor years.
Skip it if you need a listed 2019–2023 Silverado 1500 or Sierra 1500 application; K&N 81-0804 covers those GM trucks.
Consider this K&N for a listed Ford F-150 or Raptor when a 6-ounce reservoir and factory-style connections suit your installation. Confirm that the truck’s model year falls within its stated application range.
Full product details
| Brand | K&N |
|---|---|
| Item Weight | 2.5 pounds |
| Item model number | 81-0800 |
| Manufacturer | K&N Engineering, Inc. |
| Part Number | 81-0800 |
| Model | Catch Can |
| Dimensions | 13.4 x 7 x 3.1 inches |
| Additional Information | Important Information Proposition 65 Warning for California Consumers WARNING: Cancer and Reproductive Harm – www.P65Warnings.ca.gov |
Listed on Amazon as: K&N Air Oil Separator Compatible with 2011-2023 Ford F150 & 2017-2023 Ford F150 Raptor | Catch Can, Efficient Blowby Protection, 81-0800
View on Amazon#2 · Newer GM Trucks
2. K&N 81-0804 Separator
- Weight: 1.83 lb
Best for: Later Silverado and Sierra owners.
Why it ranks #2: This K&N option targets 2019–2023 Silverado and Sierra 1500 plus newer Suburban, Tahoe and Yukon applications, with a six-ounce reservoir.
K&N’s 6-ounce reservoir captures blowby oil for listed 2019–2023 Silverado 1500 and Sierra 1500 trucks, plus specified later Suburban, Tahoe, and Yukon models. The separator aims to limit oil and contaminant buildup in the intake tract and manifold, while factory-style hose connections support a more direct installation workflow.
The vehicle-specific application distinguishes this 81-0804 version from K&N’s earlier GM-truck listing: its stated coverage includes Silverado 1500 and Sierra 1500 model years 2019–2023, with listed Suburban, Tahoe, and Yukon years. A 6-ounce reservoir captures blowby oil to help protect the engine and intake tract. Factory-style connections snap on and off, and the provided description estimates installation at about 30 minutes using basic tools.
- 6-ounce high-capacity reservoir captures blowby oil
- Lists Silverado 1500 and Sierra 1500 for 2019–2023
- Factory-style hose connections snap on and off
- About 30-minute installation estimate with basic tools
- Vehicle coverage is restricted to listed model years and applications.
Skip it if you own a 2014–2018 Silverado 1500 or Sierra 1500; K&N 81-0805 lists those earlier truck years instead.
Choose this separator for a listed later GM truck or SUV when its specific application matches and you want a 6-ounce reservoir. The model year matters: this listing is not the earlier-truck version.
Full product details
| Brand | K&N |
|---|---|
| Item Weight | 1.83 pounds |
| Item model number | 81-0804 |
| Manufacturer | K&N Engineering, Inc. |
| Part Number | 81-0804 |
| Model | Catch Can; Oil Separator, Chev Silverado 1500, 5.3/6.2L |
| Dimensions | 13.38 x 7 x 3.13 inches |
#3 · Earlier GM Trucks
3. K&N 81-0805 Separator
- Weight: 2 lb
Best for: Earlier Silverado and Sierra owners.
Why it ranks #3: Its listed applications include 2014–2018 Silverado and Sierra 1500 and 2015–2020 Suburban and Tahoe; the reservoir holds six ounces.
Its high-capacity 6-ounce reservoir captures blowby oil before it reaches the engine and intake tract, giving owners of specified earlier Silverado, Sierra, Suburban, Tahoe, and Yukon models targeted contamination control. Factory-style hose connections support straightforward attachment, while the included mounting bracket provides the listed hardware for securing the catch can.
K&N lists compatibility with 2014–2018 Silverado 1500 and Sierra 1500 models, plus specified Suburban, Tahoe, and Yukon years, so this is a vehicle-specific choice rather than a universal kit. The 6-ounce reservoir captures blowby oil, helping limit buildup in the intake tract and manifold. Factory-style hose connections are intended to snap on and off, and the supplied mounting bracket supports installation; the product information estimates about 30 minutes with basic tools.
- 6-ounce high-capacity reservoir captures blowby oil
- Factory-style hose connections snap on and off
- Mounting bracket is included
- Listed installation time is about 30 minutes with basic tools
- Compatibility is limited to the listed vehicle years and models.
Skip it if you own a 2019–2023 Silverado 1500 or Sierra 1500; K&N 81-0804 lists those later truck years instead.
Choose this K&N separator if your listed earlier GM truck or SUV is the intended application and you want a 6-ounce reservoir with factory-style connections. Its fitment is specific, so the model year and vehicle must match the stated applications.
Full product details
| Brand | K&N |
|---|---|
| Included Components | Catch Can, Mounting Bracket |
| Item Weight | 2 pounds |
| Manufacturer | K&N Engineering, Inc. |
| Part Number | 81-0805 |
| Manufacturer Warranty Description | 3 Months |
| Model Number | 81-0805 |
#4 · Subaru AOS
4. IAG Performance Subaru AOS
- Weight: 10.5 lb
Best for: Subaru WRX and STI owners.
Why it ranks #4: A dedicated air/oil separator for 2008–2014 Impreza WRX and 2008–2021 STI, with a powder-coated aluminum body and ORB ports.
An aluminum-body air/oil separator for specified Subaru Impreza WRX and STI years targets oil in the intake tract, where the listing connects buildup with hose and connection damage. Its powder-coated black finish and ORB ports are named construction details, while the stated application covers WRX 2008–2014 and STI 2008–2021 models.
Keeping oil out of the intake tract can help avoid oil coating the intake, intercooler, and piping, which the product information says may contribute to premature rubber or silicone hose failure and failed connections. The aluminum body has a powder-coated finish, and the stated ORB ports provide a named connection feature. Fitment is restricted to Impreza WRX 2008–2014 and STI 2008–2021, making model and year selection essential.
- Application covers Impreza WRX 2008–2014
- Application covers STI 2008–2021
- Aluminum body with powder-coated black finish
- ORB ports are specified
- The listed 10.5-pound weight makes this a relatively heavy assembly to handle.
Skip it if you own a listed F-150 rather than a Subaru; K&N 81-0800 lists 2011–2023 Ford F-150 and 2017–2023 Raptor applications.
This is for Subaru Impreza WRX owners in the listed 2008–2014 range and STI owners through 2021 who want to limit oil in the intake tract. Check the exact model-year application before choosing it.
Full product details
| Brand | IAG Performance |
|---|---|
| Item Weight | 10.5 pounds |
| Item model number | IAG-ENG-7181BK |
| Manufacturer | IAG Performance |
| Part Number | IAG-ENG-7181BK |
| Dimensions | 12 x 10.5 x 6 inches |
Listed on Amazon as: IAG Performance Air/Oil Separator (AOS) for Subaru Impreza WRX 08-14, STi 08-21 (Black)
View on Amazon#5 · F-150 Fitment Range
5. EVIL ENERGY F-150 Catch Can
- Weight: 2.27 lb
Best for: F-150 owners wanting vehicle-specific fit.
Why it ranks #5: The vehicle-specific can lists 2011–2025 F-150 5.0L and EcoBoost fitments, as well as selected Raptor and Expedition applications.
A listed 3-ounce EVIL ENERGY catch can covers several F-150 engines and years, including specified Raptor and Expedition applications, making it a vehicle-specific option rather than a universal kit. Its baffled design separates oil particles from PCV or CCV air, with the stated aim of reducing intake-valve gunk accumulation.
The compatibility list spans F-150 5.0L, 3.5L EcoBoost, and 2.7L EcoBoost applications, plus specified Raptor and Expedition models, so the vehicle and engine determine whether it is suitable. The 10AN baffled can separates oil particles from PCV/CCV air to help limit intake-valve gunk. Product information also describes use without a breather filter in line between PCV hoses, or with a breather filter as a vent system for pre-PCV cars.
- 3-ounce baffled catch can
- Lists several F-150 engine and year applications
- Also lists specified Raptor and Expedition applications
- 10AN design separates oil particles from PCV/CCV air
- The 3-ounce capacity is smaller than the 6-ounce K&N 81-0800 reservoir.
Skip it if you need a listed 2011–2023 F-150 or 2017–2023 Raptor with a larger reservoir; K&N 81-0800 specifies those applications and 6 ounces.
This suits owners of the listed F-150, Raptor, or Expedition configurations who want a baffled separator for PCV/CCV air. Its 3-ounce capacity is the relevant boundary, so consider whether that size meets your setup.
Full product details
| Brand | EVIL ENERGY |
|---|---|
| Item Weight | 2.27 pounds |
| Item model number | EV07385BK |
| Manufacturer | EVIL ENERGY |
| Part Number | EV07385BK |
| Package Dimensions | 8.86 x 8.07 x 3.86 inches |
Listed on Amazon as: EVIL ENERGY Oil Catch Can for F150 5.0L EcoBoost Raptor 3OZ
View on Amazon#6
6. RHAOCZIYAUTO CCV Assembly
- Weight: 1.56 lb
Best for: Super Duty diesel replacement buyers.
Why it ranks #6: This replacement CCV separator assembly lists 6.7L Super Duty applications and replacement number PC3Z-6A785-A, but fitment should be verified carefully.
A replacement crankcase vent valve and air oil separator assembly for specified Ford Super Duty 6.7L Powerstroke models gives owners a vehicle-specific route to address the crankcase ventilation component. Its listed replacement number, PC3Z-6A785-A, helps identify the part, while the stated design aims to reduce engine back pressure without affecting performance.
The fitment listing covers F-250 through F-550 Super Duty trucks with 6.7L Powerstroke diesel engines for 2023–2026, as well as specified 2011–2022 old models. That range makes checking the exact truck year and engine central to the purchase. The assembly uses a compact crankcase design, which the listing says helps reduce back pressure and optimize engine layout; its replacement number offers another reference when identifying the required component.
- Listed for specified Ford F-250, F-350, F-450, and F-550 Super Duty applications
- Covers listed 6.7L Powerstroke diesel model years
- Replacement number PC3Z-6A785-A is supplied
- Compact design is stated to reduce crankcase back pressure
- Fitment is limited to the listed Super Duty 6.7L Powerstroke applications.
Skip it if you need a universal can or a listed F-150 application; EVIL ENERGY EV07385BK specifies several F-150 engines and years.
Consider this assembly when replacing the crankcase ventilation component on a listed Super Duty 6.7L Powerstroke. Its compact design and stated back-pressure aim are relevant, but the truck’s year, engine, and replacement-part identification need to align.
Full product details
| Brand | RHAOCZIYAUTO |
|---|---|
| Item Weight | 1.56 pounds |
| Item model number | PC3Z-6A785-A |
| Manufacturer | RHAOCZIYAUTO |
| Part Number | RH-26N7Y22 |
| Model | Air Oil Separator Assembly |
| Package Dimensions | 16.89 x 6.18 x 5.2 inches |
Listed on Amazon as: CCV Filter Engine Crankcase Vent Valve Air Oil Separator Assembly
View on Amazon#7
7. EVIL ENERGY 300ml Catch Can
- Weight: 0.91 kg
Best for: Universal-kit setup planners.
Why it ranks #7: The universal kit includes a 300 ml aluminum can, baffle, breather filter, 3/8-inch hose and adapters, but requires user-verified sizing and mounting.
A 300 ml aluminum can, six adapters, and a breather filter make this EVIL ENERGY kit configurable for a range of custom installations. Its 3/8-inch hose and M161.5 inlet and outlet threads give buyers concrete sizing details to compare with their existing plumbing, while the included bracket and clamps support mounting and connection work.
This is a universal, non-vehicle-specific kit, so the 0.8-meter hose length, 3/8-inch inner diameter, and M161.5 ports are useful checkpoints before installation. Six adapters provide options for connecting the can, while two hose clamps and a bracket support assembly and mounting. The 300 ml aluminum container has a baffle and supplied steel wool; measure the original hose and check mounting space to determine whether the setup suits your vehicle.
- 300 ml aluminum catch can
- Includes breather filter and baffled can
- Six adapters, two hose clamps, and mounting bracket included
- 0.8-meter hose with 3/8-inch inner diameter
- Universal fit requires checking hose diameter, fittings, and available mounting space.
Skip it if you want a vehicle-specific F-150 kit; EVIL ENERGY EV07385BK lists multiple F-150 engine and model applications.
This kit suits hands-on buyers assembling a custom catch-can setup who can verify hose and port dimensions before fitting it. The included adapters and bracket help with configuration, but it is not vehicle-specific and mounting space still matters.
Full product details
| Brand | EVIL ENERGY |
|---|---|
| Capacity | 300 ml |
| Compatible with Vehicle Type | Car |
| Included Components | 3/8" NBR Fuel Hose x1, 300ml Oil Catch Can x1, Adapter x6 + Hose Clamp x2 + Steel Wool x1, Bracket + Installation Guide |
| Item Weight | 0.91 kg |
| Manufacturer | EVIL ENERGY |
| Part Number | KT01300BK-AMZ1 |
| Material | Aluminum |
| Model Number | KT01300BK-AMZ1 |
Listed on Amazon as: EVIL ENERGY Oil Catch Can, 300ml Baffled Catch Can Kit with Breather Filter
View on AmazonAvoiding fitment and routing mismatches
The most important compatibility trap is treating every catch can or separator as a universal, inline replacement. The K&N 81-0800, 81-0804 and 81-0805 list defined truck applications, while the IAG Performance Subaru AOS is for specified WRX and STI model years. EVIL ENERGY 300ml Catch Can is explicitly universal, but its instructions call for checking original hose inner diameter, fitting needs and available mounting space; its included hose is 3/8 inch ID and connections are M16×1.5.
Those details do not establish that it suits every engine’s PCV routing. The RHAOCZIYAUTO CCV Assembly is a replacement-style part with a stated Ford Super Duty 6.7L application and replacement number, not a generic add-on.
Before choosing, match the engine, model year, connection layout and intended ventilation path. When catalog fitment is ambiguous, confirm with the vehicle maker or a qualified installer rather than adapting hoses by guesswork.
What an oil separator can—and cannot—prevent
A separator can collect oil carried in crankcase ventilation, but these listings do not establish a universal service interval or guarantee that it will prevent engine damage. The products show different collection approaches: K&N describes a six-ounce reservoir; EVIL ENERGY offers a baffled 300 ml can; and IAG describes an air/oil separator for Subaru applications. Captured liquid must be monitored and removed according to the product and vehicle instructions.
A neglected can can fill, while a poor hose connection or incorrect routing can undermine the intended separation and may create a ventilation problem. The universal can’s removable baffle and breather-filter option also make configuration relevant: its listing distinguishes a breather arrangement for pre-PCV cars from an inline setup without the filter.
Do not assume those modes are interchangeable. Check installation guidance for your exact vehicle, inspect hoses and fittings, and treat a separator as one part of crankcase ventilation—not a cure for an underlying engine fault.
How to Choose an Air Oil Separator
Vehicle and engine fitment
Look first for an explicit match to your vehicle, engine and model year; a product labeled universal still needs connection and space checks. K&N 81-0800 lists 2011–2023 F-150 and 2017–2023 Raptor applications, while K&N 81-0804 covers specified 2019–2023 GM trucks and SUVs. The IAG Performance Subaru AOS is limited to WRX and STI model-year ranges, and the RHAOCZIYAUTO assembly names 6.7L Super Duty applications.
EVIL ENERGY 300ml Catch Can requires the buyer to verify hose ID and fitting size. A vehicle-specific truck owner should favor the matching K&N or IAG product; a custom setup may consider the universal can only after confirming dimensions and routing.
Separator type and configuration
Choose a product designed for the ventilation system and job you have, rather than relying on the word separator alone. The K&N listings describe vehicle-specific catch cans with six-ounce reservoirs; the IAG product is an AOS for named Subaru applications, and the RHAOCZIYAUTO part is a replacement CCV assembly. EVIL ENERGY 300ml Catch Can is a baffled universal kit with a breather filter, while the F-150-specific EVIL ENERGY can is described as a baffled can for PCV/CCV air.
These descriptions represent different installation contexts, not a direct performance comparison. Buyers seeking a listed replacement assembly should investigate the RHAOCZIYAUTO fitment; owners wanting a vehicle-specific add-on can start with the matching truck or Subaru option.
Confirm installation method before selecting.
Capacity, fittings and installation
Check reservoir size, hose connections and included hardware against your available space and maintenance preferences. K&N’s three listings specify a six-ounce reservoir and factory-style hose connections, with installation described as taking about 30 minutes. The universal EVIL ENERGY kit lists 300 ml capacity, 3/8-inch-ID hose, M16×1.5 inlet and outlet threads, adapters, clamps and a bracket.
These capacities are stated in different units and do not by themselves show separation efficiency or service frequency. The kit’s multiple fittings may suit a custom installation, but its hose size and mounting space must match the vehicle.
A buyer prioritizing stated factory-style connections should favor the correct K&N application; a custom builder may prefer the kit’s included adapters if the dimensions align.
Which Air Oil Separator Fits My Vehicle?
Start with the vehicle-specific match. For a 2011–2023 F-150 or 2017–2023 Raptor within its listed fitment, choose K&N 81-0800 Separator; its six-ounce reservoir and factory-style hose connections make it the leading pick here. Owners of the listed newer Silverado, Sierra, Suburban, Tahoe or Yukon applications should compare K&N 81-0804 Separator, while earlier listed GM trucks and SUVs point to K&N 81-0805 Separator.
For a compatible WRX or STI, IAG Performance Subaru AOS is the dedicated AOS option. EVIL ENERGY F-150 Catch Can covers a broad stated range of F-150 engines and selected related models, but verify the exact fit.
Choose RHAOCZIYAUTO CCV Assembly only when its replacement number and Super Duty application match. The universal EVIL ENERGY 300ml Catch Can is for confirmed custom sizing and routing.
Frequently Asked Questions
How often should an air oil separator or catch can be drained?
There is no single interval established for these products in the supplied listings. Check the reservoir regularly after installation to learn how quickly it collects fluid under your driving conditions, and drain it before it becomes full. Follow the product instructions for its specific drain procedure and inspection guidance.
Does an air oil separator need cleaning or maintenance in cold weather?
Cold-weather maintenance depends on the unit, vehicle, and operating conditions; the supplied listings do not specify a universal schedule. Inspect the separator and its hoses more often in freezing conditions, check for accumulated fluid or blockage, and follow the manufacturer’s instructions. Do not assume that a catch can is maintenance-free.
Can I install a catch can without changing my vehicle’s factory PCV routing?
It depends on the specific product and vehicle. The K&N F-150 81-0800 listing describes factory-style hose connections, but that does not establish compatibility for other vehicles or products. Confirm the exact application and installation instructions before purchase, and do not alter factory PCV routing unless the product instructions call for it.
How do I choose between a vehicle-specific separator and a universal catch can?
Start by checking the exact vehicle, engine, and model year against the product’s listed application. The editorial pick is vehicle-specific, while the universal 300ml catch can is intended for confirmed custom sizing and routing. If fitment or hose routing is unclear, verify it before choosing rather than assuming universal means direct-fit.
What should I verify before buying a replacement CCV assembly?
Match the replacement number and vehicle application to your existing component before ordering. The listed CCV Filter Engine Crankcase Vent Valve Assembly is identified for a Super Duty application in the editorial guidance, but the supplied information does not provide a complete fitment list. Check the exact part number and vehicle details.
Final Words
Choose by exact vehicle fit first, then consider the product type and installation approach. The K&N 81-0800 leads for its listed F-150 and Raptor applications, while the other vehicle-specific options serve particular GM, Subaru, or Super Duty applications. The universal catch can is for confirmed custom sizing and routing.
Before buying, verify the engine, model year, application, and instructions; after installation, inspect and drain the unit as needed.
