What's the car odometer reading when this happens ?

At 230K odo with a bit of tik tak sound, as suggested by lsm , it's likely valve clearance lari .........
in particular when no valve adjustment was ever done on this engine, ever.
One doesn't have to remove cylinder head to adjust valve clearance by competent mechanics and it involves only replacing gasket for valve cover .......... and I don't call this as 'top overhaul' which equates to more $$$.

As for coloured smoke , it is quite difficult to 'see' with untrained eyes and it may be wise to refer to an honest mechanics. Btw, what's the oil brand/viscosity grade/API ACEA specs that this engine has been using before and during oil consumption occurs ?

This post has been edited by zeng: Oct 14 2017, 01:07 PM

For a wira dipstick , that 40 % means 0.4 L.
But, over how many km ?

Any blue smoke on cold morning start ? and during acceleration/decelaration ?

This white smoke of yours on cold morning start, is equivalent to 'blue' smoke I enquire about.
As stated above and I quote:

This white smoke indicates your car engine valve seals are hardened , and leaking oil from cylinder head into combustion chamber.
IF there is coloured smoke during acceleration/deceleration, it indicates piston rings are leaking engine oil from combustion chamber to engine crankcase.

This post has been edited by zeng: Oct 15 2017, 09:34 PM

You may have a point in water condensation playing a part with white smoke on morning start , though not expressly saying so.For all we know, there may actually be some condensation.
On top of that Senscents seems happy with spark plug conditions.

However as his engine is consuming like 0.7-0.8L engine oil in about 8000 km, plus the fact that 'bluish' colour smoke is very difficult to 'see' by untrained eyes , hence my position above on valve seal leaks.

Coloured smoke during quick acceleration or quick deceleration , in my humble opinion, would indicate engine oil leaking through stuck piston rings . I wish he can get someone to test this possibility for him.

What's the car model and odometer reading ?

My wira 1.5 had been on 15W40 since a top overhaul in 2003 or so, no noticeable oil leaks at 7000-9500 km oil change.
Last May switch to Total Energy 10W40 at good bargain .
Why not consider Petronas 3000/Supremo 15W40, as it may help with your oil consumption problem.
I wouldn't touch a xW30 in a 300k wira.

This post has been edited by zeng: Oct 17 2017, 12:19 AM