Is it best to use 10/40w At 100000k?

[flooky]

Hey, I've just hit the 100000k mark and need todo an oil change. Ever since I got the car at 61k which had a full service history I have been using 10/40w Magnatec every 3-4k after.

With this millage is it best to stay with 10/40 or go Fully 5/30 Edge? and also once a bottle of oil has been open'd should it be used within a certain time?

Cheers

[fossie]

As long as the cars been well maintained just use the normal oil you are meant to use.. mines done 120k and i wont be chnanging a thing..