Just been to top up the oil (again!) on my beloved to find a slight creaming (not major) around the inside of the oil filler cap. Should I be worried/hurriedly getting it into the garage -it's warranty is up in just over a month? First thought was head gasket, but reading around it appears that there isn't a gasket on these engines, it's sealant, and they're not prone to going, especially after less than 3 years and 34k miles. What else could it be? Could it be mixing different oils (i've been topping up using synthetic Synta Oil that my old Cupra used to use; nearly two years old now) and that water has permiated into the old oil before topping up? Is there a link between it's thirst for oil (maybe a 1/3 litre every 3-4 months) and a leak somewhere allowing water to get into the system? Never any sign of any oil on the driveway or at work though. Thanks everyone.