Just wanted to know

how to switch between defferent oils i.e.

if you are runnign semi-synthetic and want to go to full synthetic

or vice versa

what will you do???

I know its not good to do top ups with different oils

but

Is it that at next oil change interval simply use the different oil ????

I run an oil cleaner (for lack of a better name) before doing my oil changes. Add it to the sump, run engine for around 15 minutes, turn engine off and pull the plug - oil is now noticeably less viscous (much runnier) and drains quite freely. It probably doesn't get rid of everything, but it's easier than without the stuff. Oh be prepared to be horrified as nasty chunckies come out teh sump :redface:

Using the cleaner might be a good idea - never done it my self tho.
Depends on oils, some of them have more cleansing features than others, but all non mineral oils are pretty cleansing, hence your conversion should be ok.
Correct, don't mix'n'macth. I think there are as many opinions about oils as there are replys to your post - but use any good quality oil and u should be ok. I use Magnatec (that's designed for Magna isn't it....???? :) ). As long as u don't get tappet noise, the oil should be ok. Worn engine tappets, thin oil - noise.
And change filter every time and don't keep oil in the engine more than say 5 months - regardless of km driven. Oil's chemical properties degenerate by age etc.
I'm looking at K&N oil filters, but no too many outlets sell them.

i am currently using mobil1 and want to switch back to semi-synthetic as mobil 1 is simply to expensive to be changed twice a year unless other wise i want to keep mitsu specified service intervals of 15000 km / yearly.