Over time, the brass orifice can erode and enlarge. This reduces the velocity of the oil spray, meaning the spinner doesn't spin fast enough to separate oil. Simultaneously, the larger hole dumps more oil into the housing than the drain can handle, causing it to overflow out of the breather. Excessive Blow-by (Engine Wear)
High crankcase pressure from worn rings can overwhelm even a functional breather, pushing oil and vapor out of every available seal and the draft tube. Key Symptoms to Watch For maxxforce 13 crankcase breather problems
The "jet plate" is a brass orifice that sprays oil onto the centrifuge to spin it. Over time, the brass orifice can erode and enlarge