Have lurking in my shed 5 litres of Gulf A40 Oil with a C3 rating and 5 litres of Petronas A40 oil with a A3/B4 rating ......can i mix the 2 oils in a 2006 911
I would stick to what Porsche recommends. Probably Mobil 1 I guess. Oil additives vary between manufacturers. Not worth taking the risk to save a couple of £'s on an oil change
Buy another 3 litres of both and have enough for your next two oil changes - though strictly speaking both oils are miscible and they do both appear in the approval listing for your model.
