teripatton

I have a 1996 Audi A4 Avant which I purchased a couple of months ago. There were a few issues with the car including the oil temperature gauge rising to180C plus. No warning lights or beeps. I have had the car serviced and they have run diagnostics and it all seemed fine for about a week and now it has started doing it again. Oil levels/coolant levels are fine and no enigine lights showing. Could it just be a faulty sensor. Can anyone help?