Originally Posted by Max Capacity
That's a dirty filter.
05-06 have them on the passenger side head as pictured and on the front of the drivers side head. You can file the top off the bolt, back it out, remove the filter without pulling the timing belt covers.
HAMMERDOWN did it and posted pictures.
I have mine removed when the new short block was assembled at the machine shop.
I gotta do my timing belt sometime this summer (at 98k miles right now), thus I plan on pulling the passenger side filter at that point. Since it's only affecting the AVCS, I'm not as worried about it. But definitely on my to do list.
I hate timing belts and the replacement dances, I've owned nothing but timing chained cars for the last decade, thus it is an unfriendly change. I'm glad that Subaru finally switched to chains for 2014 models though!