Hi, I have an 06 TDci Mondeo and have just had the aux blet tensioner changed which was rattling at tick over. It still rattles but only when started from cold and then stops after a few minutes. Is this because its new and will bed in?

The tensioner doesn't need bedding in.

Did you not get the crankshaft pulley, idlers and belt changed at the same time? I would have (and did - did mine myself). For what the parts cost it isn't really cost-effective just to change one bit of the system, as if one's gone, the rest won't be far behind it.

+1 - you have to change the whole lot, the crankshaft pully has the crankshaft damper on it, which wears out over time, Ford ones seem better built than the pattern ones ive seen, so a Genuine Ford crankshaft pully is best

Gates make a kit with the belt, tensioner and idler pullys, which is cheaper than genuine Ford but decent and has a good rep

Overall the belt is a bad design and un-nessesarily long/ complex, it tends to rattle/ vibrate at tickover with the tickover being so low and the belt stretching over time

X-Type Jaguars use (almost) the same engine and gave a different (better) design of alternator pulley, that lasts longer before it starts rattling again, this can be fitted on a mk3 Mondeo but the alternator has to be slightly modified, - read it on another forum

A new pully/ tensioner/ belt set seems to last about 50k, its as if Ford was not bothered if it was to wear out outside of warrantee (but im not that cynical - am i :) )

if you can sort out the Aux belt the injectors and the DMF, the mk3 Mondeo diesel makes a great car!

Thanks for your reply, I have not had the car long and the previous owner said the crank pully had been changed. When the tensioner was changed it did improve apart from cold start up I was hoping that would improve with time but it seems I will have to get it all changed to make sure. Thanks again.

I have modified mine with a shorter belt, and my tickover is faster, so i have not had a problem since mine was modified, but i have a chum with a 2.2 that had his done recently, i will ask him what his is like