one i put in is oil cap breather. It is closed in normal driving cycle by the engine vacuum by the floating ball inside the unit. It lifts the ball up on positive crank pressure and sucks the ball back down on normal engine vacuum.You need to run PCV with catch can or breathers on both sides, not a mix of the two. You'll end up with unmetered air mimicking a vacuum leak. Surprised the car didn't throw codes or drive rough.
25.2 KB Views: 63