After researching manufacturer specifications, industry standards, and aggregated owner feedback, we compared the top air oil separators on the market. Our evaluation focuses on filtering efficiency, build quality, ease of installation, and real-world performance. Whether you drive a turbocharged daily driver or a high-performance track car, the right catch can helps keep intake valves clean and reduces oil contamination. Below are our researched picks.
| Photo | Product | Score | Buy |
|---|---|---|---|
|
🚗
|
Mishimoto Compact Baffled Oil Catch Can Best Overall Baffled design, 3/8-inch NPT ports, includes mounting hardware |
9.2 | 🛒 Check Price |
|
🚗
|
UPR Products Dual Valve Catch Can Best for High Performance Dual check valve system, 3/8-inch barbed fittings, includes bracket |
8.9 | 🛒 Check Price |
 |
JLT Performance Oil Separator Best Value Direct-fit for Ford Mustang and select vehicles, 3/8-inch barbed fittings |
8.5 | 🛒 Check Price |
|
🚗
|
Saikou Michi Oil Catch Can Best Compact Design Universal fit, 3/8-inch NPT ports, includes mounting bracket |
8.1 | 🛒 Check Price |
|
🚗
|
Billet Technology Billet Catch Can Premium Build Quality Billet aluminum, 3/8-inch NPT ports, includes stainless steel mounting bracket |
8.3 | 🛒 Check Price |
|
🚗
|
Moroso Air Oil Separator Proven Racing Heritage Universal, 3/8-inch NPT ports, includes mounting clamp |
7.8 | 🛒 Check Price |
|
🚗
|
Catch Can by Radium Engineering Innovative Design Universal, 3/8-inch barbed fittings, includes check valve |
7.6 | 🛒 Check Price |
1. Mishimoto Compact Baffled Oil Catch Can: Best Overall
The Mishimoto Compact Baffled Oil Catch Can stands out in our evaluation due to its well-engineered baffled design that effectively separates oil from blow-by gases. Based on owner feedback and the spec sheets, this unit captures a high volume of oil before it recirculates into the intake, which is critical for direct-injection engines. The billet aluminum construction and anodized finish promise long-term durability, and the included mounting hardware simplifies installation on most vehicles.
However, this catch can comes at a higher cost compared to basic models, which might deter enthusiasts on a strict budget. Additionally, the compact size may require more frequent emptying on high-mileage or heavily modified engines. Drivers with very limited space or those seeking a simple, low-cost solution may want to consider other options.
- Baffled internal design maximizes oil separation from crankcase gases
- CNC-machined billet aluminum construction with anodized finish
- Easy drain valve for quick maintenance without tools
Pros: Excellent build quality and fitment; Effective at reducing intake valve deposits
Cons: Premium price point may not suit budget builds
2. UPR Products Dual Valve Catch Can: Best for High Performance
The UPR Products Dual Valve Catch Can is designed for high-performance and boosted applications, as confirmed by our research into owner reviews and technical specs. Its dual check valve system ensures that crankcase pressure is properly managed, preventing oil from being pulled back into the intake under boost. The large capacity canister means less frequent emptying, and the included bracket allows for secure mounting.
That said, the dual valve setup adds complexity, and some users report that installation requires careful routing of hoses in tight engine bays. For those with naturally aspirated daily drivers or very limited space, a simpler single-valve catch can might be easier to live with. Also, the price is moderate, reflecting its performance-oriented design.
- Dual check valves prevent vacuum leaks and maintain crankcase pressure
- Large capacity canister reduces maintenance frequency
- Compatible with most forced induction setups
Pros: Handles high blow-by volumes effectively; Robust check valve system protects engine vacuum
Cons: Installation can be tight in cramped engine bays
3. JLT Performance Oil Separator: Best Value
The JLT Performance Oil Separator earns its Best Value badge by offering a cost-effective solution for Ford owners. Our research indicates that this direct-fit unit simplifies installation with pre-cut hoses and brackets, reducing the guesswork. The clear anodized body allows users to visually check oil levels without disassembly, which is a practical feature. Based on owner feedback, it effectively reduces intake oil buildup on compatible models.
However, this catch can is not universal; it only fits specific Ford applications, so owners of other makes will need to look elsewhere. The internal design is less sophisticated than baffled or filtered competitors, which may limit separation efficiency under extreme conditions. For general use on compatible vehicles, it provides solid value.
- Direct-fit design for specific Ford models (Mustang, F-150, etc.)
- Clear anodized aluminum body for easy level monitoring
- Includes pre-cut hoses and mounting hardware
Pros: Affordable and easy to install on compatible vehicles; Transparent body shows oil accumulation
Cons: Limited vehicle compatibility
4. Saikou Michi Oil Catch Can: Best Compact Design
The Saikou Michi Oil Catch Can is a compact, universal option that we evaluated for its space-saving design. It features a baffled interior to aid oil separation, and the CNC-machined aluminum construction feels solid. The included bracket allows flexible mounting, and the black anodized finish resists corrosion. Owner reviews highlight its effectiveness in reducing oil mist in the intake on a variety of vehicles.
Because of its small size, the canister fills up quickly, especially on engines with high blow-by. Users may need to empty it every few hundred miles, which can be inconvenient. For those with larger engines or who prefer less frequent maintenance, a larger capacity catch can would be a better choice. It is best suited for compact cars or lightly modified daily drivers.
- Compact size fits in tight engine compartments
- Baffled internal design for effective separation
- CNC-machined aluminum with black anodized finish
Pros: Small footprint ideal for limited space; Good build quality for the price
Cons: Small capacity requires frequent draining
5. Billet Technology Billet Catch Can: Premium Build Quality
The Billet Technology Billet Catch Can is a premium offering that we assessed for its construction. Machined from a single piece of billet aluminum and paired with a stainless steel bracket, it exudes durability. The internal baffle combined with filter media provides good oil separation, as supported by owner reports. It is a visually appealing component that looks at home in any engine bay.
However, the high price does not translate to proportionally better performance compared to well-designed competitors like the Mishimoto. The filter media may require replacement over time, adding to maintenance costs. For budget-conscious buyers or those who do not need the absolute best materials, this catch can may be overkill. It is best for enthusiasts who prioritize aesthetics and build quality above all else.
- Machined from solid billet aluminum for maximum durability
- Stainless steel bracket resists rust and corrosion
- Internal baffle and filter media for enhanced separation
Pros: Exceptional build quality and materials; Filter media improves oil capture
Cons: Higher price point without significant performance gain over competitors
6. Moroso Air Oil Separator: Proven Racing Heritage
The Moroso Air Oil Separator brings a racing pedigree that we considered in our evaluation. Its large steel canister offers substantial capacity, making it suitable for high-mileage or track use where blow-by volumes are high. The simple design is easy to install and maintain, and the included clamp allows secure mounting. Owner feedback from racing communities praises its reliability under harsh conditions.
On the downside, the steel body can rust over time, especially in humid environments, unless it is painted or coated. The lack of internal baffling or filter media means separation relies solely on gravity and condensation, which may be less effective than modern baffled designs. For street-driven vehicles where aesthetics and maximum separation are important, other options may be preferable. It remains a solid choice for dedicated track cars.
- Proven design used in racing applications
- Large capacity canister for extended intervals
- Simple, robust construction with steel body
Pros: Large capacity reduces drain frequency; Durable steel construction
Cons: Steel body prone to rust if not coated properly
7. Catch Can by Radium Engineering: Innovative Design
The Radium Engineering Catch Can features a unique design with a clear polycarbonate tube that lets users see oil accumulation at a glance. The internal baffle and included check valve help maintain proper crankcase pressure. Based on our research, it is a functional unit that appeals to DIY enthusiasts who appreciate transparency. The compact size fits many engine bays without interference.
However, the polycarbonate tube is a potential weak point; it can become brittle and yellow with prolonged exposure to heat and oil vapors, reducing longevity. The overall build quality is not as robust as billet aluminum competitors. For those seeking a long-term solution or who live in hot climates, a metal-bodied catch can may be more reliable. It is a good entry-level option for those new to catch cans.
- Compact cylindrical design with internal baffle
- Includes a check valve to prevent backflow
- Clear polycarbonate tube for level viewing
Pros: Clear tube allows easy level checks; Check valve protects against vacuum leaks
Cons: Polycarbonate tube may yellow or crack over time
Frequently Asked Questions
What does an air oil separator do?
An air oil separator, also known as a catch can, removes oil vapors from crankcase blow-by gases before they re-enter the intake system. This prevents oil from coating intake valves, intercoolers, and turbochargers, reducing carbon buildup and potential engine damage, especially in direct-injection engines.
Do I need an air oil separator on my car?
If your vehicle has a direct-injection engine, a turbocharger, or you drive it hard (track days, towing), an air oil separator can help keep the intake clean. For naturally aspirated port-injection engines, the benefit is less pronounced, but it can still reduce oil consumption and keep the intake tract cleaner.
How do I install an air oil separator?
Installation typically involves mounting the canister in the engine bay using a bracket, then routing a hose from the crankcase vent (PCV valve or valve cover) to the separator inlet, and another hose from the separator outlet back to the intake. Most kits include all necessary hardware and instructions. Basic mechanical skills are sufficient.
How often should I empty the oil separator?
Frequency depends on engine blow-by and canister size. Under normal driving, check every 1,000 to 3,000 miles and empty when half full. For high-performance or high-mileage engines, you may need to empty more often. Some cans have drain valves for easy maintenance.
Can an air oil separator hurt my engine?
When properly installed and maintained, an air oil separator is safe. However, if the canister is not emptied regularly, it can overflow and allow oil to be sucked back into the intake. Also, poor-quality units that restrict flow can cause excessive crankcase pressure, leading to oil leaks. Choose a well-designed separator and check it periodically.
Our Verdict
After researching and comparing the top air oil separators, our top pick is the Mishimoto Compact Baffled Oil Catch Can for its excellent build quality, effective baffled design, and overall performance. For those on a budget or with specific vehicle compatibility, the JLT Performance Oil Separator offers great value. Choose based on your engine type and performance needs.
