My motor seem to be getting through oil rather quickly lately. I'm putting in half a litre every month or 2. There's no lights on the dash the engine still feels smooth and it pulls well especially in this cold weather. No leaks either. I top it up to max and I top up when the oil level light comes on.

Any ideas why. Mileage is 86k and it's the 1.6 petrol.

Any additive recomendationa as I'm reluctact putting such a thick additive in since the engine uses synthetic oil.