Well..That is probably because the Fully Sync's viscosity is too low for an aged/old engine..
As far as I know, the reason is your old engine's internal is worn and there is more clearance between parts and parts especially the piston rings etc.
So if you use Fully sync, due to the low viscosity of it, the oil will leak into the combustion chamber and thus, your engine will "makan" the engine oil while it's running.

That's all I know..Though there is a contradicting part with me..
I've also learn that the Semi-Sync's viscosity is not consistent...
At high working temperature, the viscosity of it will become thinner..more thinner than Fully-Sync...
Now I'm confused as well -.-


This post has been edited by awyongcarl: Jul 11 2008, 12:35 AM