I have some 10w40 oil semi synthetic about 2.5 litres left and a 5 litre bottle new of the same and going to change my oil and wanted to know if its ok to mix the 2 as I wanted to use the container of the 2.5 litre to store the used oil.
I've had 2.5 litre left over oil about a year in its container just used for topping up.
Cheers