I've got a question about the PCV system on a 1990 900S. Looking at the black plastic nipple that is installed in the valve cover, there are two barbed hose attachment points. One is large and has a hose that runs to the throttle body upstream of the throttle plate. The other is small and has a small vacuum line that runs to a port on top of the intake manifold. The passage from the large hose through the plastic nipple into the valve cover is completely unrestricted and allows air to flow easily in either direction. However, the small passage does not appear to allow any airflow through it at all in either direction. It seems to be nothing more than a fancy plug in the end of the vacuum line from the intake manifold. I assume air is supposed to be able to move from the valve cover to the intake manifold through this vacuum line (regulated by the in-line PCV valve). Any thoughts on drilling this passage through? Not sure if I'm misunderstanding the system or just got a bad part.