Thanks to all, replaced belt and tensioner on water pump, and p-gasket, fuel and oil filter and serviced, and just drove it 1000 miles across France and part of spain in 30'C heat at between 70-80mph. absolutely flawless. What a machine!
just picked up this 300 tdi in a 110 CSW I have been wanting for years, don’t remember this noise when buying or on 250 mile trip back???? what does it sound like?