Difference Between 10W-40 & 20W-50

[kingofspades]

I've been using ZIC and Caltex Havoline CNG, both 10W-40 & 20W-50, for quite some time. My cultus has been driven 39000 KMs. I've heard that 20W-50 is more viscous thus more suited for older engines. Is it correct?

[bilal49er]

nope
39k old engine is not 'old'
use 10w-40, or even better 5w-30
switch to 20w-50 after 100k km

[isi0000]

yes 20W50 is more viscous so it is better to use 20W50 in summer and 10W40 in winter for terrain like pakistan
and 20W50 for old engines.......yes u can say that........engines loosing compressions will become smoky when used less viscous oil such as 0W30 or may b 10W40

[Salmanali1]

dear kingofspades<SCRIPT type=text/javascript> vbmenu_register("postmenu_2882218", true); </SCRIPT>

the recommended oil for cultus is 10W/40 therefore use it without any doubt and dont ask any body becuase mostly people miss guide.

either you use Zic or Caltex use only 10W/40 in all season.

I use Zic 10W/40 in my Alto and pretty much satisfied.

[kingofspades]

Thanks guys