i done a oil change on the st170 that i picked up on sat morning... used ford filter and 4.3 litres of oil taking it to about 3mm over max on dipstick.... it was somewhere near there before i drained it too!
i have noticed ....more particularly tonight because i had the radio off in traffic that it sounds like a quite deisel on idle.... i actually thought it was the beetle tdi infront ...... i pulled over and check oil levels etc and could find nothing obvious the sound however is loudest near the cam pulleys..??? possible crank but unsure...

sounds same both cold and hot .... oil pressure never much bellow half way on guage and oil temp reads correctly used 5/30 comma oil