My brother-in-law reminded me yesterday that he still hasn't serviced the Mondeo 1.8 Zetec he bought in March 2004, 23,000 miles later. He's apparently only had the bonnet opened once in that time..... and that was by the AA. We checked it today and there was just a small blob of very black oil on the dip stick, so we topped it up with some fresh oil. Is there likely to be trouble brewing??