An oil “catch can” is a relatively cheap upgrade you can do on your vehicle, that you can do it yourself! This little can is very effective at keeping your vehicle running smoothly throughout the many miles you will drive.
So, what is the purpose of this simple device? An internal combustion engine is never perfect, and sometimes combustion pressure passes through the piston rings, down into the crankcase where the oil is stored (especially in turbo charged vehicles). In addition, the spinning parts along with the heat generated by your engine cause the oil to “volatilize” or evaporate. If these gases mix with the oil, it will cause premature degradation.
This pressure is what we call positive crankcase pressure. This pressure needs to be relieved somehow, and that relief comes via the PCV (Positive Crankcase Ventilation) system and the breather hose. A “catch can” is a device that separates oil vapor and combustion gasses from the air that is circulating through the PCV system before it is routed back into your intake system to be burned.
The gases that come from the process of internal combustion are required by law to be returned into the motor to be burned to reduce air pollution. This is done by routing that pressure through the PCV back into the air intake system. The problem with this is that the oil vapor and contaminants created in the combustion process now get trapped and cause build up in your intake system. This can cause many problems over the lifespan of your vehicle. Some things that you might notice would be worse fuel economy, a rougher running engine, issues with your throttle body, gummed up valves, and more.
The problem with this is that the oil vapor and contaminants created in the combustion process now get trapped and cause build up in your intake system.
This is where you would see the benefit of a “catch can”. It is a small container with a strainer or filter that goes in between the PCV valve and the air intake. The contaminated air and oil vapors route through the can which separates the air and contaminants before it returns back into your intake system. After installation, the only maintenance you will have to do to your catch can is emptying the contaminated oil when you do your oil change. There is no need to check it constantly. Even with Amsoil’s 15k mile oil change even a small “catch can” is enough, just don’t forget to empty it on your service.
Also check out our article on our 1 year up to 15,000 mile oil change.
Authored by Brenden M.