it could be the cam belt pulley's i'd get them changed including the water pump just for safe sake, esp if you can do it yourself, i'v a 1.8, S reg mondy and i'v got the same noise mine wasn't the cam pulley's though like i thought i changed my belt and it was still there, mine is the aux belt idler pulley, i found this out by spraying the aux belt pulley's with wd40 and the noise stopped, the only difference is my rattle is only on cold start up really and it's quiet under load.

hope this helps a little anyway, and for the record i also think the mondeo's handle well mine usually pisses all over the little boy racers