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Oil Catch Cans Explained: What They Do, How They Work & Why Your Commodore Needs One

Posted on by Chris Milne

If you’ve ever popped your bonnet and spotted oily residue in the intake or noticed your car puffing a little more smoke than usual, there’s a good chance your engine’s crankcase ventilation is doing what it’s meant to — but sending oil vapour where it doesn’t belong. That’s where an oil catch can comes in.

At Lowe Fabrications, we design and build Australian-made oil catch cans to fit neatly in popular Holden Commodore engine bays — because a clean, dry intake system isn’t just about looks, it’s about performance and longevity. Oh, and we accidentally made a couple oil catch cans that would fit plenty other models aswell!

What Does an Oil Catch Can Do?

An oil catch can is a simple but effective filtration device that captures oil vapour, moisture, and blow-by gases before they re-enter your intake system.

Inside your engine, combustion pressure escapes past the piston rings (known as blow-by). This pressure carries fine oil mist and fuel vapour that needs to be vented from the crankcase. On a stock setup, that vapour is routed back into the intake — where it coats your throttle body, intercooler, and intake valves with oily residue.

An oil catch can intercepts that flow, separates the oil and contaminants, and stores them in a sealed chamber. The result?

  • A cleaner intake system

  • Reduced detonation risk

  • Better long-term performance

  • Less carbon build-up on valves (especially in direct-injection engines)

Vented vs. Recirculating Oil Catch Cans

When it comes to oil catch can design, you’ll hear two main terms thrown around — vent-to-atmosphere and recirculating. Both serve the same purpose but suit different setups.

Vented to Atmosphere Oil Catch Cans

Commodore Catch Can by Lowe Fabrications - Lowe Fabricatsion

These systems release filtered crankcase gases into the air through a breather filter. They’re common in race and off-road setups where emissions compliance isn’t required and simplicity is a priority.

Pros:

  • Simple, effective, no vacuum draw needed

  • Keeps the intake completely oil-free

  • Great for performance and boosted engines

Cons:

  • May not meet emissions rules in some states

  • Can produce a mild oil smell under hard driving

Recirculating Oil Catch Can Systems.

Recirculating Oil catch Cans Lowe Fabrications

A recirculating system routes cleaned crankcase vapours back into the intake after filtration, maintaining a closed-loop system that keeps ECU readings and emissions legal.

Pros:

  • Emissions-friendly

  • Ideal for road cars or engineered setups

  • Cleaner presentation (no breather filter)

Cons:

  • Slightly more complex hose routing

  • Some oil vapour may still enter the intake

At Lowe Fab, we manufacture both — including a bolt-on billet lid kit that converts your vented catch can to a recirculating version.

Lowe Fab Oil Catch Cans – Built for Real Cars

Lowe Fabrications battery sized oil catch can with dual -12 ORB ports, -6 drain, and K&N panel filter

Our catch cans aren’t universal tins. Each is designed around the Holden Commodore engine bay and available in multiple finishes including satin black, raw, or custom colours. Every unit features:

  • Internal baffles for efficient oil separation

  • -12AN female fittings and -6AN drain ports

  • K&N filters (for vented models)

  • Billet aluminium fittings and accessories

  • Options for matching hoses and fittings

Every Lowe Fab catch can is made to order right here in Australia — built by enthusiasts, for enthusiasts.

Common Oil Catch Can FAQs

Do I really need an oil catch can?
If you care about performance and reliability, yes. Even mild engines produce blow-by, and over time it adds up.

Will an oil catch can add horsepower?
Not directly — but it helps maintain the power you already have by keeping the intake and combustion clean.

Do I need to empty an oil catch can often?
Depends on driving style. Check it every few thousand k’s — you’ll be surprised how much oil it catches.

Can I install an oild catch can myself?
Yes, if you’re handy — but we recommend professional fitting to ensure correct hose routing and sealing.

Are vented oil catch cans legal?
Rules vary by state. Always check your local regulations before fitting a vent-to-atmosphere system.

A good catch can is one of the smartest investments you can make for your Commodore — especially if it’s modified, boosted, or driven hard. It’s about keeping your engine breathing clean and performing like it should.

Explore the Full Lowe Fabrications Oil Catch Can Range HERE.

Chris Milne