I have very little clue when it comes to topping up engine oil: 5w30, 10w30, 10w40 etc.
I've no clue what's in there currently, so I'm assuming I should go by the vehicle handbook?
And following that, fully synthetic? Mobil, Castrol, or is stuff like Halfords and Tesco the same thing?
Thanks in advance, I've had trouble finding the info elsewhere, so hoped some money-mindful folk on here might have an idea :)