An Effective Catch Can Helps Protect Your Engine from Harmful Oil Residue
Repco Stocks a Range of Oil Catch Can Kits to Suit Your Car or 4WD
Modern engines are designed with advanced emissions systems that recirculate crankcase gases back into the intake system to be reburned. While this reduces harmful emissions, it also allows oil vapour and contaminants to travel through the intake tract. Over time, this can lead to carbon buildup, restricted airflow, and reduced engine efficiency. An oil catch can is designed to intercept these vapours before they enter the intake system, helping to maintain cleaner internal components and more consistent performance.
Repco offers a selection of oil catch can kits engineered to suit a wide range of petrol and diesel vehicles, including popular 4WDs. Brands such as Flashlube and Ryco are known for producing reliable oil separation systems that are built to withstand demanding driving conditions. With many modern diesel engines equipped with exhaust gas recirculation (EGR) systems, preventing intake contamination is increasingly important, particularly given the high cost of intake manifold and EGR cleaning services.
What Does a Catch Can Do?
A catch can plays a preventative role in maintaining engine cleanliness. During normal combustion, a small amount of combustion gases escapes past the piston rings and enters the crankcase. This is known as blow-by. These gases contain oil mist, unburnt fuel vapour, moisture, and other contaminants. The positive crankcase ventilation (PCV) system redirects these gases back into the intake manifold to reduce emissions.
Without filtration, the oil vapour within these gases can settle on intake valves, throttle bodies, intercoolers, and intake manifolds. In direct injection engines, fuel does not wash over the intake valves, meaning oil deposits can accumulate more rapidly. Over time, these deposits can contribute to rough idle, hesitation, reduced power, and increased fuel consumption. A catch can captures much of this oil vapour before it reaches sensitive components, helping to minimise carbon buildup and preserve engine efficiency.
How Does a Catch Can Work?
An oil catch can is installed inline with the crankcase ventilation hose, typically between the valve cover and the intake manifold. As blow-by gases travel through the hose, they are redirected into the catch can’s internal chamber. Inside the canister, a series of baffles, mesh filters, or separation chambers slow the airflow and promote condensation.
As the gases cool and change direction within the chamber, oil droplets and heavier contaminants separate from the air and collect at the bottom of the can. The filtered air is then routed back into the intake system to be safely reburned. Periodically, the collected oil and residue must be drained from the catch can to maintain effectiveness.
High-quality catch cans are sealed systems that do not vent to atmosphere. This ensures emissions compliance while still providing effective oil separation. The design and internal structure of the can significantly influence its efficiency, making quality components important for long-term reliability.
Are Catch Cans Legal?
The legality of installing a catch can varies depending on jurisdiction and vehicle classification. In Australia, oil catch cans are legal provided they remain part of a sealed system and do not vent crankcase gases directly into the atmosphere. Vent-to-air systems may breach emissions regulations and are generally unsuitable for road vehicles.
It is important to ensure that any modification does not interfere with factory emissions control systems or vehicle compliance requirements. Vehicle owners should confirm local regulations and consider warranty implications before installation. Properly fitted, sealed catch cans are widely used on diesel 4WDs and performance vehicles as a preventative maintenance upgrade.
Does My Engine Need a Catch Can?
While not every engine strictly requires a catch can, certain designs benefit significantly. Direct injection petrol engines are particularly prone to intake valve carbon buildup due to the absence of fuel wash. Turbocharged engines often generate higher crankcase pressures, increasing blow-by and oil vapour circulation. Diesel engines, especially those equipped with EGR systems, can accumulate heavy carbon deposits when oil vapour combines with soot particles.
Older engines with worn piston rings may also produce higher levels of blow-by gases. If you notice excessive oil residue in intake piping, recurring EGR issues, or intake manifold contamination during servicing, a catch can may provide added protection. As a preventative measure, it can help extend service intervals and maintain smoother engine operation over time.
How Easy Is It to Install a Catch Can?
Most modern catch can kits are designed with ease of installation in mind. Vehicle-specific kits typically include mounting brackets, pre-cut hoses, fittings, and clear instructions. Installation involves mounting the can securely within the engine bay and rerouting the crankcase ventilation hose through the catch can assembly.
For those comfortable working with basic hand tools, installation can often be completed within one to two hours. Care must be taken to ensure airtight connections and correct hose routing to prevent vacuum leaks or performance issues. In more complex engine bays, or where access is limited, professional installation may provide added peace of mind.
Regular maintenance of the catch can is essential. The collected oil and residue should be drained periodically, with frequency depending on driving conditions and engine type. Vehicles subjected to heavy towing, off-road use, or high-performance driving may require more frequent checks.
Repco’s range of oil catch cans provides practical solutions for drivers seeking to protect their engine from long-term contamination. By reducing oil vapour buildup within the intake system, a properly installed catch can supports improved airflow, more consistent combustion, and enhanced engine longevity. Whether for a daily driver, touring 4WD, or performance vehicle, investing in preventative maintenance components can contribute to lower long-term servicing costs and improved reliability.
To further support engine health, consider complementary products such as high-quality engine oil to reduce internal wear and vapour formation, an oil filter designed for efficient contaminant removal, and an EGR or intake system cleaner to help manage carbon deposits. Maintaining these related components alongside a catch can provides a comprehensive approach to protecting your engine and optimising performance.
