i see..
next oil change i will try to use other brand.
we've been using castrol for a long time now, my dad's been using it for his diesel engine (passenger jeep) for almost eleven years now. but hes always on time for his oil changed.
me, i've been using it for five years ever since i got our datsun from my father in law.
and it's just lately that this problems arises.
let's just say it's a hand me down car. but i really love this pick up.