focus loud fan and odd idiling

[Celt]

Recently iv noticed my fan is quite loud and idling alternates about 100 rpm. I heard it could be the fan belt on its way out. Is it likely or can I just ignore it? Not overly keen on a massive repair bill.

[Zad]

Fan belt? You should tell them its not 1981

It is a long long (long long...) time since Fords ran the radiator fan off the engine. Even my 1991 Sierra has electric fans, and that is on an in-line engine, on a transverse it gets a bit complicated. Sounds to me like the sensor switch has failed in the "on" position and needs replacing. Or do you mean it is making a whining / grinding / whatever noise? With the engine off and cold, see if you can spin the fan around by hand, it should be easy to rotate.

Varying idle speed is usually a sticking Idle Control Valve. Get a can of carb cleaner and remove the valve, give it a good clean out. It can also be a leaking hose somewhere in the system, but I would go for the ICV first.