Is it worth installing a catch can?

For most drivers, a catch can isn’t essential and won’t deliver dramatic performance gains. It can help limit oil vapors in some engines and may reduce carbon buildup, but the benefits depend on engine design, driving style, and how the system is installed and maintained.

This article examines what a catch can does, how it interacts with the PCV system, who might benefit, and the risks to consider before adding one. It also offers practical guidance on installation and upkeep and how to decide if it’s right for you.

What a catch can does and how it fits the PCV system

To understand whether you should install one, it helps to know what a catch can is supposed to do. A catch can sits in the PCV (positive crankcase ventilation) line and is intended to trap oil vapors that would otherwise travel from the crankcase into the intake. By intercepting these vapors, a catch can can, in theory, reduce carbon buildup and keep intake components cleaner on some engines.

Before considering the potential benefits, note this: the PCV system is part of your vehicle’s emissions control and engine breathing. Altering it with a catch can changes the flow of vapors and vacuum, so installation must be careful and compatible with your vehicle’s design.

• Reduces the amount of oil-laden vapors reaching the intake manifold, which can help curb carbon buildup on direct-injection engines.


• Can limit oil deposition in intercooler piping and turbo systems, potentially helping maintain consistent airflow in boosted engines.


• May decrease oil burning via the intake path in some setups, though results vary by engine and how the system is configured.


• Typically needs to vent back into the intake (or be carefully managed) to avoid emissions violations and to keep the PCV system balanced.

Bottom line: the benefits are real in specific situations, but they are not universal and depend on engine design and maintenance.

Pros and reasons to consider

Before you decide, it helps to know what advocates point to as potential advantages of installing a catch can.

• Cleaner intake tract in engines prone to oil vapor buildup, especially direct-injection designs vulnerable to carbon deposits on intake valves.


• Potentially reduced carbon buildup in throttle bodies and intake runners over the long term, which can help maintain throttle response and efficiency.


• Benefit for high-mileage or enthusiast setups where oil vapor management is a concern, particularly in boosted or turbocharged engines.


• Peace of mind for some owners who want to manage oil vapor independently as part of a larger maintenance or performance plan.

In practice, the perceived gains will vary. For many daily drivers, the improvement may be subtle rather than dramatic.

Cons and important caveats

It’s also important to weigh the potential downsides and risks associated with catch cans.

• Improper installation can disrupt the PCV system, causing vacuum leaks, rough idle, or crankcase pressure changes that can trigger codes or leaks.


• Some configurations, especially venting to atmosphere, can conflict with emissions regulations or local laws, and may be illegal for on-road use in certain regions. Vented-to-intake designs are generally preferred for legality and emissions compliance.


• Maintenance is required: catch cans must be emptied and cleaned regularly, and hoses must be inspected for cracks or oil saturation, or performance can degrade.


• There is a risk of creating a vacuum or flow restriction if the can, hoses, or fittings are not rated for automotive use or become clogged.


• Some OEMs discourage aftermarket PCV changes or warn that improper installations could affect warranty coverage.

Conclusion: the decision should balance the engine you have, how you drive, and your ability to install and maintain the system correctly and legally.

Who should consider installing a catch can and best practices

Not all engines or owners will benefit equally. Here are common scenarios where people evaluate a catch can.

• Owners of direct-injection engines seeing carbon buildup on intake valves or throttle bodies, particularly as mileage increases.


• Owners of turbocharged or high-boost engines where oil vapors can carry into intercoolers and piping, potentially affecting performance consistency.


• Enthusiasts who are comfortable performing or supervising maintenance and who understand the emissions implications and warranty considerations.


• Owners who want a measured, professional approach to oil vapor management rather than relying solely on OEM PCV design.

If you do decide it’s worth pursuing, consult a qualified technician who understands your vehicle’s PCV system and any local emissions or warranty implications. In some cases, a properly configured, closed-loop catch can routed back to the intake is the safer and more compliant option.

Installation considerations and maintenance tips

Key factors to keep in mind before or during installation include the quality of the unit, how hoses are run, and how you maintain the system.

• Choose a high-quality, purpose-built catch can with proper baffling and a reliable one-way valve or venting path back to the intake to maintain proper PCV function.


• Route hoses carefully to avoid kinks, heat exposure, or contact with moving parts; ensure there’s a clear drain or sump for easy maintenance.


• Keep the can in a accessible location and monitor oil levels regularly; empty or replace contents as recommended by the manufacturer or based on driving conditions.


• Follow manufacturer guidance and consider professional installation to ensure compatibility with your vehicle’s PCV system and emissions controls.


• Confirm compliance with local laws and warranty terms; some regions require emissions-compatible (closed-loop) configurations.

Bottom line: proper selection, installation, and maintenance are essential for any potential benefit to be realized without introducing new issues.

Summary

A catch can can offer targeted benefits in engines prone to oil vapor-related carbon buildup, especially direct-injection or turbocharged setups. For most everyday drivers, the improvement is modest and must be weighed against potential risks to the PCV system, emissions compliance, and maintenance requirements. If you decide to pursue one, invest in a quality, properly installed, emissions-friendly configuration and stay on top of regular upkeep. Always consider your engine type, warranty, and local regulations before proceeding.

Do you really need a catch can?

Reduced Engine Knock: Oil buildup in the intake system can lead to pre-ignition or engine knock, which can cause damage to the engine over time. Oil catch cans help mitigate this risk by preventing oil vapor from contaminating the intake air and causing irregular combustion.

How beneficial are catch cans?

Oil catch cans are often fitted as an aftermarket accessory to optimise engine performance. They help reduce emissions to ensure a vehicle complies with regulations. They help protect engine parts from contaminants.

Why are oil catch cans illegal?

Oil catch cans can be illegal because they modify a vehicle's positive crankcase ventilation (PCV) system, which is part of the vehicle's emissions control system. Altering the PCV system is often illegal in states with strict emissions standards, such as California, as it can interfere with the reintroduction of crankcase fumes into the engine for proper combustion and emission control. Some catch cans that vent to the atmosphere are explicitly illegal because they release pollutants, while others may be non-compliant if they aren't installed correctly or don't meet local regulations.
 
This video explains why oil catch cans can be illegal in some areas and when they are compliant: 1mBig Truck Lovers YouTube · Aug 27, 2025
Reasons why oil catch cans can be illegal

• Tampering with emissions systems: Installing an oil catch can is considered a modification of the factory emissions system. The PCV system is designed to route crankcase fumes back into the engine to be burned, which reduces air pollution. 
• Venting to atmosphere: Many catch cans have an air filter that vents to the atmosphere, releasing pollutants and making them illegal in many areas with strict emissions laws. 
• Disrupting engine function: Some catch cans can alter the flow of air and pressure in the engine, potentially causing the engine to run less efficiently. 
• Visual inspection: During an emissions test, a visual inspection may identify the catch can as a non-compliant modification, leading to a failed inspection. 

When catch cans might be legal

• Closed-loop systems: Some catch cans are designed to be compliant because they maintain a closed-loop system by venting clean air back into the intake, but this requires specific, non-venting designs. 
• Local regulations: The legality varies greatly by location. Some states may allow them, while others, like California, have much stricter rules. 
• CARB-compliant models: If a model is specifically certified by the California Air Resources Board (CARB) and is installed correctly, it may be legal to use in California. 

You can watch this video to learn more about the effects of oil catch cans: 1mAuto Expert John CadoganYouTube · Jul 18, 2018

What are the disadvantages of a catch can?

Disadvantages- continual maintenance, draining, replacing filters if fitted. Failing to, can cause positive crankcase pressure, resulting in seal and gasket failures.