Assalam O Alaikum Pakwheelers, My dad has a indus corolla 1.6 limited edition 1999 model. It's got genuine 432k-433k kms. He got done an overhaul about 56-57k kms back. Its lowering oil for some time now, but this time, it is like 60% of oil left in the engine with almost 4000kms. We check it everyday. What could be the cause? Can it be the PCV valve or some piston rings issue? The engine chamber has a slight leak it just moistures the under of the engine chamber, but it is not enough for that much of a loss of engine oil. We use Toyota Taglon 10w-40 engine oil and change the oil every 4000kms. It doesn't emit any black/blue smoke. Apart from the white smoke in the morning on the cold start. Please provide your opinions on this topic.