Previously, I mentioned the situation I am currently facing with my car that is making me look into oil catch cans. (You can read here https://torquepost.wordpress.com/2013/05/05/oil-catch-cans-what-you-should-know-the-backstory/). That got me to do some searching, and researching, and researching on my researching so I could do better searching, and I searched.
The reason it took so much looking is because I found out that not all oil catch cans are created equal. As a matter of fact, unfortunately, the oil catch can is one of those products where you run the risk of buying cheap junk that is just a copy of another brands copy of a legitimate brand. Even worse, the oil catch can is supposed to have other parts inside of it, and you run the risk of simply being charged for an empty can without the bits inside that are required for the can to actually do its job of catching oil. Sometimes, this isn’t bad if you just want a can to modify and you intend on opening it up. But if you need to buy one ready, read on.
First off, lets explain how catch cans work. The purpose of a catch can is to take what is being sent out through the positive crankcase ventilation (PCV) valve, and separate the actual oil that may come out, collect it, and send just air and vapors back to the intake manifold, as opposed to the PCV system sending both air, vapors, and oil back in the intake manifold. The goal is to avoid getting oil into the intake manifold. Oil is meant to lubricate, and unless you drive a diesel, you should not be burning it in any way.
For turbocharged cars, the purpose of an oil catch can is incredibly important. The can should work to prevent blow by of oil, which could lead to dangerous situations of coating couplers, causing them to slide off under boost, coating the fins inside an intercooler which drastically decreases its efficiency, and ultimately end up cooking inside your turbo, contributing to a nasty condition of what is called “oil coking” where the oil turns to a charcoal like substance in the turbo over time. In addition, you don’t want any blow by on your pistons either.
To do this, a catch can works by having one line of high quality hose that can withstand heat and enormous pressure created by the engine, running from the PCV valve into one inlet on the catch can. From there, it goes into a tube of some sort, and past a filter. The oil should collect at the bottom. Catch cans come in different sizes to hold more or less oil. The filter is to prevent any oil from then escaping back out of the catch can through the other outlet and hose that will run back to the intake manifold. Different companies will make their own filter medium and inlet designs, and some serious performance applications may have baffles inside to absolutely prevent any oil in the can from sloshing around and returning through the outlet.
Now how do you choose one and avoid getting ripped off? Read on in part three of this series.