I always had dust in mine (had adjustable cam gear and no cover)
Anyway my car always did it, despite the fact during its 140k life (until I sold it) I never changed the PCV valve and never replaced any of the idler pullies for the timing belt.
Hector
2003 Rally Red Mitsubishi Evolution VIII
257HP/259TQ
2005 Lapis Blue Mazda 6s
RET: 00 Cabernet Red Ford Contour Zetec ATX SUPERCHARGED
160HP/141TQ
