Salam alaikum, digging an old thread still, just would like to share a personal experience with my previous carby cultus, faced the same problem of oil coming out in the air box, and the same failed attempted to stop the oil spill with a piece of cloth, checked n found damaged pcv valve, replaced with a new one costed me Rs.700/- but still the problem persisted, my car was driven like 150k kilometres. I was told that the engine has weakened and needs to b overhauled, a normal overhaul would cost anyone for a cultus not more than Rs 30.000/-, another reasons could be, as i was told, increase in RPM over 3000, This problem is common with margalla, khyber and cultus, (as far as i ve learned about it)