Oil Catch Can: How They Work and Why You Might Need One

The oil catch can is an aftermarket device that’s attached into the car's cam/crankcase ventilation system. If you've ever seen the engine bay of a highly-modified car, you may have seen one of these mechanisms up close and wondered what they're for. Here's how they work, and why you might want to have one in your vehicle.

The problem with standard engines

When combustion occurs in your engine, compacted gas gets ejected through the exhaust system. Ideally, all gases should exit the engine this way, but sometimes, pressure seeps past the piston rings, and the gases find their way into the crankcase instead. When this happens, an engine blow-by occurs, which can lead to serious engine wear, increased fuel consumption, engine misfires, and very expensive repairs.

Engines have built-in systems to prevent this blow-by from happening: these are called crankshaft ventilation systems. Unfortunately, they are far from perfect. The way these systems are built, oily air can get into the engine’s cylinders, which can build up sludge over time. This is when an oil catch can become useful.

The purpose of an oil catch can

To put it simply, the oil catch can is just an additional filter, relying on the fact that oil is heavier than air to do its work. This device typically contains steel wool or baffle system to separate the oil from the air. The oil then falls to the bottom of the can where it stays until the can is cleaned. Even a budget can can do wonders in preventing oil from wreaking any havoc in the cylinders.

If you own a car with a direct-injection engine, an oil catch can will be especially beneficial. Direct-injection engines shoot fuel straight into the cylinder, which means there’s nothing keeping oil accumulating in the cylinders. An oil catch can prevents that from happening.

Bottom line

An oil catch can doesn’t have any performance-enhancing properties. However, it does ensure that your intake tract is free of oil and gunk. Good quality cans cost between PHP1,000 to PHP2,000. If you ever decide that you need one for your car, make sure to clean the can with some regularity.