Someone just in the last week or so, posted a way to see if your oil breather box is clogged. As I happened to have "flame traps" on my weekend to do list, I gave the method a try. Too cool! Just use a couple feet of 5/8" ID hose (i.e. a garden hose) to actually blow into your breather box. With the oil cap removed, you should easily blow into the box. Slide your hand over the oil filler area, and your blowing becomes difficult. Remove your hand and you can blow freely. I actually had to make an adapter for one of my cars to just blow into the top of the hose that the flame trap fits into, but same deal. It is easy to tell if your box is blocked. Don't know who posted the info, but it was good stuff.