Hi, My Mondeo also has this noise problem and only started a week or so ago. The noise sounds like an old diesel double decker bus when on low revs and tick over. When you give it some revs, it goes away. When the car is cold the noise isn’t too bad, but as it warms up it get worst again. The noise is also worst when the air con is on or when the air blower is on high fan speed. Now I don’t like this noise, but I’m skint, therefore my question to you all is; if I leave it alone will I be damaging my car? Also what is an average price to sort this out? And how easy a job is it to do yourself, as my car knowledge is very limited. 2002 2.0l TDCi Thanks Al.