Have an issue with the car, 1.9cdti 150, from cold start I'll here a "tisking" sound, I think that would be the best word to describe it. its fairly loud and can be heard inside the car, will sound every 2-3 seconds for about 20 mins even when driving. Will normally disappear then but on occasions it returns when the car has been idling in traffic for a short period.

Mechanic said it was vac pump building pressure and was normal. Anyone else come across this?