air filter oil cap?

**Anti venom** · 07-20-2010, 01:02 PM

what is the purpose of replacing the oil cap with that filter out the top where the cap goes? i bout it but i forget and insted of lookin it up ill just ask ha. and is it neccesary?

**Shakingchevy** · 07-20-2010, 03:51 PM

if it is what i am thinking...it makes it breath better...but it isn't nessesary

**pajeff02** · 07-20-2010, 04:33 PM

There is always some amount of blowby within the engine and these combustion gases need to be drawn out or vented. In modern engines, the PCV (Positive Crankcase Ventilation) system draws the gases back into the combustion chamber via the intake vacuum. Old school systems simply had a downdraft tube that extended below the vehicle and the passing air helped draw the blowby out of the engine.

In some cases, crankcase pressure becomes excessive and it is necessary to either modify the PCV system or add a breather. On our cars, a separator system or newer style PCV is sometimes warranted as oil can also be drawn into the system and cause issues.

**Anti venom** · 07-21-2010, 07:51 AM

Originally Posted by pajeff02

There is always some amount of blowby within the engine and these combustion gases need to be drawn out or vented. In modern engines, the PCV (Positive Crankcase Ventilation) system draws the gases back into the combustion chamber via the intake vacuum. Old school systems simply had a downdraft tube that extended below the vehicle and the passing air helped draw the blowby out of the engine.

In some cases, crankcase pressure becomes excessive and it is necessary to either modify the PCV system or add a breather. On our cars, a separator system or newer style PCV is sometimes warranted as oil can also be drawn into the system and cause issues.

i put on the race style headers took out all the air systems. and will be
instaling my ms3 cam soon. should i get the air breather oil cap? or get the catch can aswell?

**pajeff02** · 07-21-2010, 08:07 AM

Originally Posted by Anti venom

i put on the race style headers took out all the air systems. and will be
instaling my ms3 cam soon. should i get the air breather oil cap?

Did you remove the PCV system? The AIR system is something entirely different and has no impact on blowby gases.

**Anti venom** · 07-21-2010, 11:41 AM

no i did not remove the pcv that i know of just the air and egr. but should i get one anyway?

**pajeff02** · 07-21-2010, 11:51 AM

Can't say... if you get oil in the intake or the dipstick lifts out of its tube then you have issues that need to be addressed. The addition of a catch can is not a bad idea no matter what as that separates the oil and prevents it from entering the intake.