The mondeo mk1/mk2 were fitted with a 6 cylinder, 24 valve 2.5 V6 engine, and only those, if yours is a mk2 mondeo ST200 (it would be imperial blue?) then it will be a 2.5 V6, the ST200 engine is different to the normal 2.5 V6 engine but only in the ST200's they just have different inlets, cams, throttle body etc, but other than that the bare bones of the engine are the same.

The 3.0 V6 is the ST220 which is fitted to MK3 mondeos and i think they were only 2003 maybe late 2002 onwards? Yours will or should have a 2.5 V6 engine in it, i doubt very much it would have had the 3.0 engine fitted.