Catch can what is

With the hopes of it collecting at the bottom of a container, some drain back into the oil pan, some do not. The air coming out the otherside of the can then enters back into the intake after passing a PCV check valve. These valves insure that air enters in a one way fashion. This style system can be a vacuum leak if simply disconnected and not capped off, and can change how your tune acts.

Additionally, because the air is brought back into the engine, it will contain a certain amount of particulate. This is why factory intakes usually are oily and sludgey on the inside. However, that cleanliness is not the only drawback. Oil being present in a fuel charge can cause detonation and tune issues.

On a Nitrous or Boosted engine it is even more detrimental. For a modified and high horsepower application, this is really the only logical choice.

An Open system will also be more effective at removing the crank case pressure as a whole. It has Direct Injection! Port Injection sprays onto the stems of inlet valves washing them.

And the muck that builds up on inlet valves comes through the PCV hose. I should have picked that up from your article. Car Advice.

To explain, we fitted one to our Ford Ranger…. Tags: oil change. Newsletter Signup First Name: Email address:. Notify of. Oldest Newest Most Voted. Every PCV system works the same way — there is a PCV breather valve that sits atop the engine valve cover, which vents the blow-by through a hose and into the intake manifold to route it back into the engine. The solution is to use an oil catch can, which is a canister that has a filter and baffles in it along with two hoses to connect to the valve cover and the intake manifold.

When oil blow-by occurs, the mixture is sent into the oil catch can, which filters it and circulates the air back into the combustion chamber. It should be noted that it is very rare not to see an oily residue on the inlet tract walls of a diesel engine, and while it may sometimes appear to be excessive, this is usually the result of minute quantities of oil that escape past the seals of even new turbochargers. Therefore, unless there is liquid oil anywhere in the inlet tract, you do not need an oil catch can.

However, if you are planning on buying a well-used, or high mileage diesel vehicle that does, or may consume excessive amounts of engine oil under certain operating conditions, fitting a well-made oil catch can from a reputable manufacturer may very well save you many thousands of dollars.

By fitting such a device, you will be protecting both the catalytic converter and the diesel particulate filter against the effects of excessive hydrocarbon loads.