Title pretty much explains,
I change my oil every 4-6k miles depending on how generous I’m feeling, however will the oil dirty oil that’s already in the sump mix with the clean oil when topping up?
Normally I just top up but in this case I have had to drain about half a litre out on two occasions
First when I changed the oil as I overfilled
Second when topping up (overfilled again after 3k miles)
so it's had quite a bit of new oil mixed with the original stuff, just wondering will the new stuff mix fine with the old, if not I’m going do an early change and try not to be such a dope when topping up.