Oil catch cans are simple devices that can greatly benefit direct-injected engines. They prevent oil and other contaminants from causing buildup inside your engine's intake manifold. ... A typical catch can plugs into a hose running from the top of your engine's crankcase to the intake manifold.

What is the point of a catch can?

An oil catch tank or oil catch can is a device that is fitted into the cam/crankcase ventilation system on a car. Installing an oil catch tank (can) aims to reduce the amount of oil vapors re-circulated into the intake of the engine.

Do you really need a catch can?

When it comes to the question of whether or not you need an oil catch can, the guiding principle should always be the amount of oil that the vehicle uses, or the amount of oil that is present in the inlet tract. ... Therefore, unless there is liquid oil anywhere in the inlet tract, you do not need an oil catch can.