15-30W Engine oil? for 150,000k's?

[aaronng]

So burning oil does not have anything to do with Piston ring being loose / Worn? - only the PVC valve?

It does have to do with the piston ring and bores with worn. What happens is that the combustion gases at high pressure pass between the piston ring and wall (called blowby) and get into the crankcase. The combustion gas causes the crankcase to have higher pressure, which then is released by the PCV valve back into the intake manifold. If you have this problem, then usually the pressure is enough to cause even a new PCV valve to open. So in this situation, replacing the PCV valve won't solve the entire problem, but can help partially.

The amount of oil burnt depends on the amount of gas being released by the PCV into the intake manifold and that in turn is affected by a weak/worn PCV valve spring and worn piston rings and bores.

[andiiso]

It does have to do with the piston ring and bores with worn. What happens is that the combustion gases at high pressure pass between the piston ring and wall (called blowby) and get into the crankcase. The combustion gas causes the crankcase to have higher pressure, which then is released by the PCV valve back into the intake manifold. If you have this problem, then usually the pressure is enough to cause even a new PCV valve to open. So in this situation, replacing the PCV valve won't solve the entire problem, but can help partially.

The amount of oil burnt depends on the amount of gas being released by the PCV into the intake manifold and that in turn is affected by a weak/worn PCV valve spring and worn piston rings and bores.

great explanation, mine burns oil quite quick, im using 0w-40 mobil1 gold (only cos i needed oil real bad but its not bad doesnt burn that badly) since my car done like 180,000kms i mite actually replace PCV valve regardless of it being worn or not (after 180,000kms, i think it would have worn weakened in some way or another) and im gonna go bak to my mobil1 silver 5w-50 .. not too concerned bout the .01kw in my car depending on oil, i cant realli feel a difference anyway, as long as i get enuff protection in my old engine and it run fine, salll gooodddd .. my car is a Civic VtiR btw