I got the TSpark serviced last thursday the 1st Feb. So oil tank full. Drove to Donegal from Dublin and back then a week of Dublin City driving. Result? Needed just under a litre of oil. That works out at about one litre per 5 hundred miles. Drove to Omagh and back yesterday, about 200 miles. Needs about half a litre now. It's like I've to fill her in both tanks every week. Is this the average? I basically have to top her up every second week.